€alumUa  WLnihzvgit?  \^>\^ 
in tfic Cit j> of iSeiu ^or fe  c^d>\ 

College  of  ffl&psitwnsi  anb  burgeons 


Reference  Htbrarp 


\ 


HANDBOOK 


OF 


ANATOMY 

BEING  A 

COMPLETE  COMPEND  OF  ANATOMY 

INCLUDING  THE  ANATOMY  OF  THE  VISCERA,  A  CHAPTER  ON 
DENTAL  ANATOMY,  NUMEROUS  TABLES,  AND  INCORPO- 
RATING THE  NEWER  NOMENCLATURE  ADOPTED 
BY  THE   GERMAN   ANATOMICAL    SOCIETY, 
GENERALLY  DESIGNATED  THE  BASLE 
NOMENCLATURE,  OR  BNA. 

BY 

JAMES  K.  YOUNG,  M.D.,  F.A.O.S. 

Professor   of    Orthopaedic    Surgery,    Philadelphia   Polyclinic;    Associate   Professor 

of   Orthopaedic    Surgery,    University   of    Pennsylvania;    Orthopaedic    Surgeon 

to    the     Philadelphia    General     Hospital:     Fellow    of    the    College    of 

Physicians,  of  Philadelphia;   Fellow  of  the  Philadelphia  Academy 

of  Surgery;  Fellow  of  the  American  Orthopaedic  Association; 

Member  of  the  American  Medical  Association,  etc.,  etc 


FIFTH    EDITION,    REVISED    AND    ENLARGED 

WITH  154  ENGRAVINGS,  SOME  IN  COLORS 


PHILADELPHIA 

A.    DAVIS  COMPANY,   Publishers 
English  Depot 
Stanley  Phillips,  London 

1918 


Copyright,  1889 
Copyright,  1905 
Copyright,  1909 
Copyright,  1913 
Copyright,  1917 

BY 
F.  A.  DAVIS  COMPANY 

Copyright,   Great   Britain.     All   Rights  Reserved 


Philadelphia,  Pa.,  U.  S.  A. 

Press  of  F.  A.   Davis  Company 

1914-1916  Cherry  Street 


PREFACE  TO  FIFTH  EDITION. 


The  demand  for  a  new  edition  of  the  author's  Handbook 
of  Anatomy  has  afforded  him  an  opportunity  to  revise  certain 
portions  of  the  volume,  made  necessary  by  recent  advances  in 
anatomical  studies  since  the  publication  of  the  fourth  edition. 

In  order  to  enhance  still  further  any  value  that  the  work 
may  possess,  there  have  been  some  eliminations,  many  altera- 
tions and  a  large  number  of  additions.  These  changes,  together 
with  the  replacement  of  the  older  cuts  in  the  chapter  on  Osteol- 
ogy by  clearer  and  far  superior  illustrations,  that  comprised  an 
osteologica]  atlas  in  former  editions,  necessitated  a  recasting 
of  the  entire  hook. 

A  special  "chapter  devoted  to  Dental  Anatomy,  comprising 
the  Anatomy  of  the  Face.  Teeth  and  daws,  properly  illustrated, 
lias  been  prepared  by  Joseph  L.  Appleton,  dr..  B.S.,  D.D.S.,  of 
The  Thomas  W.  Evans  .Museum  and  Institute  of  Dentistry, 
I  Fniversity  of  Pennsylvania. 

In  order  to  make  the  work  thoroughly  accurate  and  mod- 
ern, it  wa-  deemed  advisable  to  incorporate  throughout  the 
volume  the  Basle  nomenclature  or  UNA  as  formulated  and 
adopted  by  the  German  Anatomical  Society.  Each  anatomical 
name  has  been  critically  examined  and  its  UNA  equivalent 
added.  This  is,  perhaps,  the  only  medium-sized  anatomical  work 
that   fully  include-  the  newer  terminology. 

This  arduous  labor  ha-  been  successfully  prosecuted  by  Dr. 
Samuel  Lewald,  medical  and  historical  writer,  without  whose 
valuable  assistance  this  portion  of  the  work  could  not  haw  been 
accomplished. 

The  author  trusts  that  these  numerous  changes  will  meet 
with   the   approval   of   professors   and    teachers    in    the   leading 

medical    and    dental    colleges,    and    that     it     may    appeal    to    the 

-tudeiit  body  in  general,  for  whom  this  labor  has  been  under 

taken. 

d.    K.    Y. 
222  S...  Sixteenth  Street. 

run 


PREFACE  TO  FOURTH  EDITION. 


Although  for  over  twenty  years  the  book  has  been  in  con- 
stant use  by  large  numbers  of  students  and  approved  by  professors 
and  teachers  in  leading  medical  colleges  and  in  Nurses'  Training 
Schools  generally,  comparatively  few  errors  or  omissions  of  im- 
portance have  been  discovered;  but  in  the  present  edition  these 
have  all  been  noted  and  corrected.  The  appreciative  thanks  of 
the  author  are  extended  to  Dr.  A.  C.  Pole,  of  Baltimore,  for 
several  pertinent  suggestions  in  the  preparation  of  this  edition. 

J.  K.  Y. 


(iv) 


PREFACE  TO  THIRD  EDITION. 


In  the  preparation  of  this  new  edition,  the  author  has  taken 
advantage  of  the  opportunity  to  correct  the  few  clerical  errors 
which  must  necessarily  lie  round  in  a  comprehensive  though 
condensed  work  upon  Anatomy,  and  to  make  such  changes  as 
have  become  necessary  through  the  advances  of  the  science  since 
the  publication  of  the  last  edition. 

In  the  section  upon  the  Nervous  System  the  greatest  changes 
will  be  found,  the  first  part  having  been  rewritten. 

In  the  description  of  the  Muscular  System,  the  regional 
grouping  has  been  retained,  because  it  is  more  practical  for  the 
student. 

Attention  is  directed  to  the  original  colored  plates  of  the 
Arterial  System  which  offer  the  most  complete  classification  of 
all  the  arteries  in  the  smallest  space,  ami  also  to  the  original 
diagrams  of  the  sensorj  tracts  from  spinal  cord  to  brain,  and 
the  motor  tracts  from  brain  to  spinal  cord. 

The  author  desires  to  express  his  gratitude  to  the  student 
body  of  America  tor  their  continued  confidence  in  this  early 
literary  effort  of  his,  and  express  the  hope  that  the  present  edit  ion 
may  he  as  well  received  as  the  others. 

J.  K.  V. 


(v) 


PREFACE  TO  SECOND  EDITION. 


The  demand  for  a  new  edition  has  afforded  an  opportunity 
to  thoroughly  revise  the  text  and  illustrations,  and  to  add  such 
changes  of  description  and  nomenclature  as  have  been  intro- 
duced into  modern  methods  of  teaching. 

Whenever  it  seemed  necessary  or  advisable  sections  have 
been  entirely  rewritten,  but  the  same  attention  to  conciseness  and 
accuracy  has  been  observed  as  in  the  former  edition. 

The  size  of  the  pages  has  been  considerably  enlarged  and 
increased  in  number,  and  the  illustrations  increased  from  76  to 
171.  Many  improved  cuts  replace  those  used  in  the  former  edi- 
tion and  full-page  engraved  plates  have  been  inserted  in  the  text 
where  they  will  be  most  serviceable. 

In  its  preparation,  the  last  editions  of  both  Morris  and  Gray 
have  been  freely  consulted,  so  that  it  can  be  Used  with  either  of 
these  standard  works. 

As  in  the  former  edition,  although  prepared  particularly 
for  students,  sufficient  descriptive  matter  has  been  added  to 
render  it  valuable  to  the  busy  practitioner,  particularly  in  the 
sections  upon  the  Yiscera,  Special  Senses,  Vascular  System,  the 
Nervous  System,  and  Surgical  Anatomy. 

Special  attention  has  been  given  to  the  anatomy  of  the  brain 
and  nervous  system,  which  will  be  found  to  compare  favorably 
with  the  descriptions  in  larger  works. 

The  author  has  been  much  gratified  to  observe  the  tenacity 
with  which  students  and  physicians  have  retained  the  work  for 
reference. 

The  author  would  acknowledge  his  obligation  to  Dr.  Eichard 
F.  Gerlach,  who  has  distinguished  himself  by  his  careful  and 
accurate  work  upon  Deaver's  "Surgical  Anatomy,"  for  valuable 
assistance  upon  the  revision. 

J.  K.  Y. 

(vi) 


PREFACE  TO  FIRST  EDITION. 


The  object  of  this  little  book  is.  as  its  title  indicates,  t<> 
furnish  a  concise  though  complete  synopsis  of  human  anatomy 
for  the  use  of  students  of  medicine  and  others. 

Appreciating,  from  a  personal  contact  with  students,  the 
limited  time  at  their  disposal  and  the  unlimited  amount  of 
medical  material  to  be  digested,  the  author  has  endeavored,  by 
well-selected  wood-cuts,  typographical  arrangement,  and  numer- 
ous tables,  to  facilitate  the  acquisition  of  a  subject  as  difficult  as 
it  is  essential,  and  elegance  of  diction  has  therefore  been  sacri- 
ficed to  conciseness  and  accuracy. 

In  its  preparation  the  last  edition  of  Gray's  "Anatomy" 
[edited  by  Keen],  as  the  work  most  largely  employed,  has  been 
selected  as  the  standard,  but  Leidy,  Quain,  Allen,  Holden,  Eenle, 
Schaffer,  Klein,  Brown  Aids,  and  others,  have  been  freely  used, 
and  on  the  special  subjects  Link,  Spiegelberg,  Savage,  Sehroeder, 
Budin,  Treve's  "Surgical  Applied  Anatomy."  and  the  "Ameri- 
can System  of  Dentistry"  have  been  consulted.  Although  pre- 
pared particularly  for  students,  sufficient  descriptive  matter  has 
been  added  to  render  it  valuable  to  the  busy  practitioner,  par- 
ticularly the  section-  on  the  Viscera,  Special  Senses,  Vascular 
System,  ami  Surgical  Anatomy.  The  aim  throughout  has  been 
to  make  it  as  thoroughly  complete  and  accurate  as  possible,  and 
at  the  same  time  readily  accessible  for  reference  or  study. 

The  writer  would  acknowledge  hi-  obligations  to  Messrs. 
S.  X.  Durborow  and  C.  W.  Holly,  medical  -Indents  at  the  Uni- 
versity, for  assistance  in  the  correction  of  proof. 

.1.  K.  V. 

(vii) 


CONTENTS. 


PAGE 

T  NTRODUCTORY      1 

(  >STEOLOGY    3 

The  Frontal  Bone    8 

Parietals    10 

The  <  tecipital  Bone    12 

Temporals    15 

The    Sphenoid     20 

The   Ethmoid    24 

The   Lachrymal    26 

The   Malar    27 

The  Superior  Maxilla    29 

Palate    Bones     •'■- 

The  Inferior  Turbinated   Bonea    ;{-l 

The  Vomer    35 

The   Inferior    .Maxilla    :!:> 

The  Sutures  and  Fontanelles    39 

Fossae  of   skull    40 

The  Orbits    42 

Foramina  at  the    Base  of  the  Skull    46 

The   Sternum    •'- 

The  Ribs    •v- 

The  Spine   5fl 

The   Upper   Extremity    (i:i 

The     Ann      ~_[) 

The    Forearm    '- 

The    Hand     7,i 

The  Lower  Extremity    sl 


The  Thirii 


86 


Th<-    Patella     sn 

The  Log           w 

The   Fool n:< 

Table  of  Ossification    " 

Abticulatioks    uid   Ligaments         In| 

The   Thors  i            "'!l 

The  Pelvis       "- 


x  CONTENTS. 

PAGE 

The  Muscular  System  128 

Muscles  of   the  Head 129 

Muscles  of   the   Neck    133 

Vertebral    Region     136 

Muscles  of  the  Back 138 

Muscles  of  the  Abdomen    143 

Muscles  of  the  Upper  Extremity    147 

Muscles  of  the   Forearm    140 

Muscles  of  the  Hand    153 

Muscles  of  the  Lower  Extremity 155 

Muscles  of   the   Leg    160 

Muscles   of   the    Foot    163 

The   Fascias 165 

The  Heart  and  Vascular  System    170 

The  Circulation  of  the  Blood    176 

The   Arterial    System    178 

Table  of  the  Arterial  System   202 

The  Venous   System    209 

The  Lymphatic  System    218 

The  Alimentary  Apparatus   223 

The  Teeth    224 

The   Pharynx    230 

The  (Esophagus    231 

The    Abdomen    232 

The  Peritoneum    235 

The    Stomach    238 

The.  Small  Intestine    240 

The  Large  Intestine    242 

The    Pancreas     245 

The   Liver 246 

The   Ductless   Glands    '. 250 

Vocal  and  Respiratory  Apparatus   254 

The   Larynx    254 

The   Trachea    and    Bronchi    259 

The    Lungs    261 

The    Pleura?     264 

The  Mediastinum    264 

The  Genito-Urinary' Apparatus   266 

The  Kidneys  266 

The  Bladder 270 

Male    Organs    .  . 273 

Female    Organs    ; 283 

The  Mammary  Gland    292 


CONTENTS. 


\i 


PAGE 

The  Nervous  System    294 

The    Brain     298 

The   Cranial    Nerves    ;;_»:; 

The   Spinal    ( 'ord    332 

The   Spinal   Nerves    :;.!2 

Table  of  Spinal   Nerves    :;4:: 

The   Sympathetic   Nervous   System      350 

Organs  of  Special  Sense   355 

The  Nose    355 

The    Eye    356 

Appendages  <>i  the  Eye  ■ 372 

The    Ear    375 

Tlic    Tongue    •.  388 

Tlic  Skin  and  Appendag  ■  •    389 

Surgical  Anatomy    :>!>l 

Triangles  <>f  the   Neck    .' 391 

Triangle  in    Front  of   Elbow-joint    :!'.i4 

Scarpa's   Triangle    394 

Axilla     395 

Anatomy  of  I  ternia   396 

[schio-rectal  Region  and   Perineum    4o-_! 

Anatomy  of   Lateral   Lithotomy   407 

Dental    Anatomy    4i)'.) 

Index    42;; 


ILLUSTRATIONS. 


FIG.  PAGE 

1.  Frontal    bone,    outer    surface    7 

2.  Frontal    bone,    inner    surface    9 

3.  Parietal    bone,    outer    surface    10 

-1.     Parietal    bone,     inner    surface     11 

5.     Occipital     bone,     outer    surface     12 

u.     Occipital    bone,    inner    surface    13 

7.  Left  temporal   bone,    outer   surface    15 

8.  Left  temporal   bone,    inner  surface 16 

9.  Left  temporal   bone,   inferior  surface  of  the   petrous   portion    17 

10.  Section  of  the  temporal   bone  through   the  middle  car,   etc 19 

11.  Sphenoid    bone,    upper    surface    21 

12.  Sphenoid    bone,    anterior    surface    22 

13.  Ethmoid     bone     25 

14.  Lachrymal    bone    26 

15.  Xasal    bone    27 

16.  Malar    bones     2S 

17.  Superior    maxillary    bone    29 

18.  Superior   maxillary,    inner   surface    ' 30 

19.  Palate  bone   (viewed  posteriorly)    32 

20.  Palate    bone    (inner    surface)     32 

21.  Inferior    turbinated    bones    34 

22.  Vomer    35 

23.  Inferior   maxillary    bone    3G 

24.  Left  half  of  inferior  maxillary  bone,   inner  surface   37 

25.  The    hvoid    bone    38 

26.  Fossae    of    skull    41 

27.  Facial    portion    of   skull    43 

28.  Nasal    meatuses    45 

26     I'.ase  of  skull,   external   surface  47 

30.  Floor    of    the    cranium    49 

31.  Sternum   and   costal   cartilages    51 

32.  The    peculiar    ribs    53 

33.  The   vertebral    column,    or   spine    55 

34.  A    dorsal    vertebra    56 

35.  A    cervical     vertebra     57 

36.  The    atlas     57 

37.  The    axis    58 

38.  Seventh    cervical,    or    vertebra    prominens    58 

39.  Peculiar    dorsal    vertebra?    59 

40.  A    lumbar    vertebra    , 60 

41.  The    sacrum,    anterior    surface    61 

42.  The   sacrum,    posterior   surface    62 

43.  The  left   clavicle,    upper   surface    64 

41.     The    left   clavicle,    under    surface    65 

45.  The    scapula,    anterior    surface    66 

46.  The   scapula,    posterior    surface    67 

47.  The  humerus,  anterior  surface  69 

is.    The   humerus,    posterior   surface    69 

!!>.    Flna  and    radius,    anterior   aspect    73 

50.  Radius    and    ulna,    posterior    aspect 75 

51.  Carpus,   metacarpus,   and   phalanges,   dorsal   surface   77 

Carpus,   metacarpus,  and  phalanges,  palmar  surface   79 

innominatum,    outer    -'nine.       82 

54.    Ok   innominatum,    Inner   surface   83 

."..",.      The    femur,     anterior    surface     87 

56.     The    femur,     posterior    surface    87 

.".7.    The  tibia  and   fibula,  anterior  surfac     91 

58.     The  tibia   and  fibula,   posterior  Burfaci 91 

50.      The    tarsus,    metatarsus,    and    phalanges.    Mi       Si       lirfai        95 

60.    The  tarsus,   metatarsus,   and    phalanges,    plantai    surface    !<7 


(Xi 


i) 


x}v  ILLUSTRATIONS. 

FIG.  PAGE 

61.  The    thorax    Ill 

62.  The    pelvis 112 

63.  The    shoulder     115 

64.  The    elbow 117 

65.  The    knee    123 

66.  The    knee 123 

67.  Muscles   of   the   back 139 

68.  Muscles    of    the    abdomen    144 

69.  The    diaphragm     145 

70.  Muscles  of  the  shoulder  and  arm   149 

71.  Triceps    muscles     149 

72.  Posterior  superficial   muscles   of  the   forearm    151 

73.  Muscles  of  the  anterior  femoral  region   157 

74.  Muscles  of  the  posterior   femoral   region    157 

75.  Anterior  muscles  of   the   leg    161 

76.  Posterior   muscles   of   the   leg    161 

77.  Right   side   of   heart    171 

78.  Diagram    of   the    foetal    circulation 177 

79.  Arteries    of    the    face    182 

80.  Internal    maxillary   artery    184 

81.  The  arteries  of  the  head  and  neck.     (Colored)    Pacing  184 

82.  The  arteries  of  the  upper  extremity.     (Colored)    Facing  186 

83.  Abdominal    aorta    195 

84.  The  arteries   of  the  trunk.      (Colored)    Facing  196 

85.  The   arteries  of  the   lower  extremity.    (Colored)    Facing  198 

86.  Temporary    teeth     226 

87.  Permanent    teeth     227 

88.  Pharynx,   laid  open   from    behind    231 

89.  Regions  of  the   abdomen    232 

90.  Abdominal    viscera     235 

91.  The    peritoneum     236 

92.  The    liver    247 

93.  Transverse  section   of  lobules  of  liver   24S 

94.  Vertical    section    of   larynx    •. 256 

95.  Heart  and   lungs 263 

96.  Longitudinal   section   of   kidney    : ■ 267 

97.  Diagram  of  the  course  of  the  uriniferous   tubules    269 

98.  Male   organs   of    generation    275 

99.  The   testicles    and    epididymis    277 

100.  Vertical   section   of  testicle   279 

101.  Internal    female   genitals    283 

102.  Female   organs    of    generation    ' 285 

103.  Section  of  an  ovary   287 

104.  External   female   genitals    289 

105.  Surface   anatomy   of   the    myelencephalon    300 

106.  Left   side   of   human    cerebrum    303 

107.  Convolutions  and  fissures  of  the  median  and  tentorial  surfaces  of  the 

right   cerebral    hemisphere 305 

108.  Inferior   aspect  of   cerebral    hemisphere    307 ' 

109.  The   lateral    ventricles   and    choroid   plexus    309 

110.  Mesial  section  of  brain  and   brain  stem   313 

111.  Interior   of  mesencephalon    317 

112.  Diagram  of  sensory  tracts  from  spinal   cord   to  brain    319 

113.  Diagram  of  motor  tracts  from  brain  to   spinal  cord    321 

114.  Scheme  of  the  nuclei  and  root-fibers  of  the  cranial  nerves   323 

115.  Base  of   brain   and   cranial    nerves    324 

116.  Optic,  oculomotor,   trachlear,   and  trifacial  nerves   Facing  324 

117.  Facial    and    auditory    nerves 327 

118.  Glossopharyngeal,    pneumogastric,    spinal    accessory,    and    hypoglossal 

nei-ves    329 

119.  Cervical    plexus    and    branches    333 

120.  Section  of  the  spinal  cord  and  membranes    ....  334 

121.  Brachial  plexus   and   branches    " 335 

122.  Lumbar  plexus  and  branches   Facing  338 

123.  Sacral   plexus   and   branches    Facing  342 

124.  The  sympathetic   system    Facing  350 

125.  The  olfactory  nerves  and  nerves  of  common  sensation  to  the  nose  355 

126.  Nasal  meatuses  and  accessory   cavities 357 

127.  Inner  wall  of  orbit  and   adjacent  parts    358 

128.  Horizontal   section   of  right  orbit    359 

129.  Anteroposterior  section   of   eyeball    360 

130.  Vessels    of    the   eye    363 


ILLUSTRATIONS.  xv 


FIG.  PACE 

131.  The  structure  of  the  human  retina 365 

132.  Diagram    of    the    retinal    vessels    366 

133.  The    orbital    muscles    :',Tn 

1114.     The    ophthalmic    artery    and    branches    ::71 

135.  The    lachrymal    apparatus    374 

136,  External,    middle,    and    internal    ear    377 

1'.       The    auditory    ossicles     381 

138.  Organ    of    corti    ::s) 

139.  Triangles    of   the   neck    393 

140.  The    axilla     395 

141.  Dissection   of  the   inguinal   canal    ::;i7 

142.  Deep  femoral  region — the  femoral  vessels,   etc.    (McOrath)    399 

143.  Male    perineum,    superficial    dissection     402 

144.  Male    perineum,    deep    dissection     in:! 

1 15.     Female    perineum    405 

146.  Maxillary    and    mandibular   process   of    first   visceral    arch    and    fronto- 

nasal   process    409 

147.  Sutures   of   the  hard   palate    410 

148.  Four   mandibles   ranging   from   birth   to   eighteen    months    411 

149.  Muscles    of    expression    412 

150.  Tooth     development     413 

151.  Tooth    development     414 

152.  Root   growth    417 

153.  Occlusal    surfaces    of    teeth     420 

154.  Cross  section  through   roots  of  teeth   in   xitu   421 

Chart  of  cranial  nerves     Facing  422 


INTRODUCTORY. 


The  term  ''anatomy/'  derived  from  the  Greek  dva, 
"through,"  and  T€/Ave<u,  m  "to  cut,"  signifies  dissection,  but  has 
been  appropriated  under  the  general  term  Morphology,  to  the 
science  which  treats  of  the  apparent  properties  of  organized 
bodies.  It  is  the  science  of  organization  and  of  form.  Anatomy 
is  divided  into  vegetable,  which  treats  of  the  structures  and  prop- 
erties of  vegetal  bodies ;  comparative,  which  treats  of  the  anatomy 
of  animals;  human,  which  treats  of  the  anatomy  of  man  in 
a  physiological  or  healthy  state;  pathological,  which  treats  of 
the  anatomy  of  the  diseased  human  body,  etc. 

Human  anatomy  is  subdivided  into  general,  descriptive,  and 
surgical. 

General  anatomy  treats  of  the  minute  structure  or  physical 
elements  of  the  organs  of  the  body.  It  is  also  called  micro- 
scopical anatomy,  or  histology.  It  comprises  four  distinct 
elementary  tissues : — 

Epithelial,  including  mucous  membranes,  epidermis,  glands,  etc. 
Muscular,  including  striated  and  nonstriated  muscles. 
Nervous,  including  the  proper  nerve  elements. 

Connective,  including  white  fibrous,  elastic,  adipose,  cartilage,  and 
bone. 

Descriptive  or  special  anatomy  treats  of  the  various  proper- 
ties of  the  organs  arranged  into  systems;  hence  the  name 
systematic.    It  includes: — 

Osteology,   the  anatomy  of  the  bones. 

Syndesmology,  the  anatomy  of  the  joints. 
Myology,  the  anatomy  of  the  muscles. 
Angiology,  the  anatomy  of  the  vessels. 
Neurology,  the  anatomy  of  the  nerves. 
Splanchnology,  the  anatomy  of  the  viscera,  etc.,  etc. 

Surgical  <»r  topographical  anatomy  treats  of  the  relative 
position  of  organs  to  our  another  and  to  the  surrounding  parts 
in  special  regions  of  the  body,  as  the  axilla,  neck,  or  o-roin. 

(1) 


OSTEOLOGY. 


The  framework  of  the  body  is  composed  of  bones,  which 
constitute  the  skeleton.  This  in  the  adult  consists  of  206  bones, 
including  the  ossicula  auditus:  Excluding  the  ear  ossicles,  the 
number  is  200,  or  excluding  also  the  two  patella'  and  the  hyoid 
bone  the  muni)*']'  is  197.  Spine  (including  coccyx  and  sacrum) 
".V>.  cranium  8,  face  14,  ribs,  sternum,  and  os  hyoideum  26,  upper 
extremity  64,  lower  extremity  62,  ear  ossicles  6. 

The  hones  of  the  head  number  22,  consisting  of 

Eight  cranial  hours-,  the  frontal,  2  parietal,  occipital,  2  temporal, 
the  sphenoid  and  ethmoid  hones;  14  facial  bones,  2  lachrymal,  2  nasal, 
2  malar.  2  superior  maxilla'.  2  palate.  2  turbinal,  1  vomer,  and  1  in- 
ferior  maxilla. 

The  hones  of  the  trunk  number  52,  comprising 

Twenty-six  vertebrae,  7  cervical,  12  dorsal.  .">  lumbar,  1  sacrum  and 

1  coccyx. 

Twenty-six  of  the  thorax,  7  pairs  of  true  ribs,  •">  pairs  of  false  rilis. 

2  pairs  of  floating  ribs,  the  sternum  and  os  hyoideum. 

The  bones  of  the  skull,  face,  thorax,  and  vertebral  column 
arc  known  as  the  axial  skeleton,  and  consist  of  74  segments. 

The  bonea  of  the  npper  extremity  number  64,  comprising 
on  either  side  : — 

Two  shoulder,  clavicle  and  scapula;  1  arm.  humerus;  2  forearm, 
radius  and  ulna:  8  wrist  (carpus),  scaphoid,  semilunar,  cuneiform,  pisi- 
form, trapezium,  trapezoid,  os  magnum  and  unciform;  1!)  hand,  5  meta- 
carpal and  14  phalanges. 

The  bones  of  the  lower  extremity   number  62,  comprising 

on  either  side  : — 

One  hip,  divided  into  3  portion-,  the  ilium,  ischium  and  pubes; 
1  thigh,  the  femur;  2  le<_r,  tibia  and  fibula;  1  knee,  the  patella;  26  foot, 
7  tarsal  hone-,  the  astragalus,  os  calcis,  scaphoid,  cuboid,  external. 
middle,  and  internal  cuneiform;  5  metatarsal  hones,  and   14  phalanges. 

The  hones  of  the  shoulder-girdle,  npper  extremities,  pelvic 
girdle,  and  lower  extremities  are  known  as  the  appendicular 
skeleton,  and  consist  of  126  Fegments.  They  are  divided  into 
long,  Bhort,  llat  or  tabular  and  irregular. 

Long  bones,  smcli  a  femur,  humerus,  or  radius,  consisl  of 
-hafi  or  diaphysis,  and  two  extremities  or  epiphyses. 

(3) 


4  HUMAN   ANATOMY. 

The  shaft  or  diaphysis  is  a  cylindrical  tube  composed  ex- 
ternally of  compact  tissue  and  internally  of  cancellous  tissue, 
the  center  being  hollowed  out  by  the  medullary  canal. 

The  epiphyses,  or  extremities,  are  expanded  for  articulation, 
and  are  composed  of  a  mass  of  solid  cancellous  tissue  with  a 
thin  coating  of  compact  tissue. 

The  short  bones,  asi  tarsus  or  carpus,  are  small,  compact, 
irregular  cubes. 

Flat  bones\,  as  those  of  skull  and  shoulder-blade,  afford 
extensive  surfaces  for  protection  or  muscular  attachment. 

Under  irregular  or  mixed  bones  are  classed  the  vertebral, 
sphenoid,  maxillary  bones,  and  such  that  could  not  be  placed 
under  either  of  the  other  heads. 

The  surfaces  of  the  bones  are  marked  by  certain  eminences 
and  depressions,  which  have  received  the  following  names: — 

An  apophysis  is  a  prominent  excrescence  formed  directly  upon 
a  bone,  and  is  distinguished  from 

An  epiphysis,  which  has  been  formed  from  a  distinct  center  and 
separated  by  cartilage,  but  afterward  united  to  the  bone. 

A  head  is  a  rounded,  smooth,  articular  eminence  for  articulation. 

A  condyle  is  an  irregular  prominence  for  muscular  attachment. 

A  trochanter  is  a  large  prominence  for  the  attachment  of  rotator 
muscles. 

A  tuberosity  is  a  broad,  uneven  eminence. 

A  tubercle  is  a  small  tuberosity. 

A  spine  is  a  sharp-pointed  eminence. 

A  line,  or  ridge,  is  a  rough,  narrow  elevation,  extending  some 
distance. 

Others,  from  their  fancied  resemblance  to  ordinary  objects, 
have  received  the  following  names: — 

Coronoid,  like  a  crown;  coracoid,  like  a  crow's  beak;  unciform 
or  hamular,  hook-like;  malleolar,  like  a  mallet;  mastoid,  nipple-like; 
zygoma,  yoke-like;  pterygoid,  wing-like;  odontoid,  tooth-like;  spinous, 
thorn-like;  styloid,  pen-like;  rostrum,  a  beak;  vaginal,  ensheathing; 
squamous,  scaly;  conoid,  cone-like. 

The  cavities  of  bones  are  divided  into  the  articular  and  the 
non-articular. 

The  articular  are  named  acetabulum,  measure-like ;  glenoid, 
hollow;  cotyloid,  cup-like;  facet,  smooth;  trochlear,  pulley- 
like ;  alveolar,  socket-like. 

The  non-articular  cavities  are  named  notches,  fissures, 
grooves,  furrows,  fossae,  hiatus,  foramina,  canals,  sinuses,  aque- 
ducts, cells,  depressions,  meatuses,  etc. 

Composition  of  Bone. — Adult  human  bones  have  a  specific 
gravity  of  1.92,  and  are  composed  of  about  one-third  (33.30) 


OSTEOLOGY.  5 

organic  or  animal  matter,  principally  gelatin,  and  two-thirds 
inorganic  or  mineral  matter,  as   follows: — 

Gelatin  and  blood-vessels,  33.30;  phosphate,  carbonate,  and 
fluoride  of  calcium,  64.34;  soda,  sodium  chloride,  and  mag- 
nesium phosphate.  2.36 ;  total,  100. 

Structure  of  Bone. — In  structure  they  consist  of  an  ivory- 
like  compact  substance  (substantia  compacta)  inclosing  a  lamel- 
lar, recticular  cancellous  substance;  also  designated  loose  or 
spongy  bone  (substantia  spongiosa) . 

They  are  covered  with  periosteum,  and  their  cavities  are 
lined  with  endostenm  and  filled  with  medulla,  or  marrow. 

Periosteum  is  a  fibrovascular  membrane,  composed  of  two 
layers,  the  outer  formed  chiefly  of  connective  tissue,  the  inner 
composed  of  several  layers  of  elastic  fibers,  the  deepest  of  which 
is  the  "osteogenic/'  or  bone-producing  layer.  The  tendons  and 
ligaments  are  attached  to  the  periosteum  by  a  mutual  interlace- 
ment of  the  fibers. 

Endosteum,  medullary  membrane  or  internal  periosteum,  is 
a  delicate,  highly  vascular  membrane  lining  the  cylindrical 
cavity  of  long  bones. 

Medulla,  or  bone-marrow,  is  of  two  kinds,  the  red  in  the 
flat  and  irregular  bones,  and  the  yellow  in  the  shafts  of  adult 
long  bones.  The  red  marrow  (medulla  ossium  rubra)  has  few 
blood-vessels,  but  many  corpuscular  elements.  These  may  be 
divided  into  three  groups:  (1)  red,  nucleated,  true  "marrow- 
cells,"  or  myelocytes;  (2)  large,  pinkish  cells,  "myeloplaques" 
of  Robin,  supposed  to  be  the  source  of  the  red  blood-corpuscles  or 
erythroblasts ;  and  (3)  giant  cells,  or  "osteoclasts." 

The  yellow  marrow  (medulla  ossium  ftavo)  or  myelocytes 
contains  numerous  blood-vessels,  a  few  "marrow-cells,"  and  a 
large  quantity  of  fat  which  imparts  to  it  its  color. 

Blood-vessels  of  Bone. — The  arteries  consist  of  three  sete: 
The  arteries  of  the  (1)  compact  and  (2)  cancellous  tissue  are 
derived  chiefly  from  the  periosteum,  the  latter  being  larger  and 
Less  numerous.  The  medullary  canal  of  long  bones  has  (3)  one 
or  more  nutrient  arteries,  which  penetrate  tbe  compaci  tissue 
obliquely  and  divide  into  two  branches,  one  passing  upward,  the 
other  downward,  in  tbe  canal.  All  the  arteries  anastomose 
freely  with  each  other. 

The  veins  consist  of  three  sets  also:  1.  Tbe  veins  of  the 
compact  substance  are  small  and  join  the  periosteum.  2.  The 
veins  of  the  cancellous  1  issue  do  not  accompany  the  arteries,  but 
in  certain  Localities  form  large,  tortuous  channels,  as  in  the 
diploic  jreins  of  ilie  cranium.     In  the  long  bones  they  emerge 


.(3  HUMAN    ANATOMY. 

at  the  ends,  near  the  articular  surfaces.  3.  The  nutrient  arteries 
are  accompanied  by  one  or  more  large  veins,  which  emerge  at 
the  nutrient  foramen. 

Lymphatics  and  nerves  are  numerous  in  the  periosteum  and 
are  also  found  in  the  substance  of  the  bone. 

Microscopic  Appearance. — Microscopically,  bone-tissue  con- 
sists of  concentric  layers  or  lamella,  arranged,  about  the  course 
of  a  vascular  or  Haversian  canal  /4eooo  mcn  i11  diameter.  In 
and  between  these  plates  of  bone-tissue  are  minute  cavities,  or 
lacuna?,  each  containing  a  bone-cell,  or  "osteoblast/'  and  from 
which  diverge  in  every  direction  minute  canals,  or  canaliculi, 
connecting  the  lacunas  with  each  other  and  with  the  Haversian 
canals.  Each  canaliculus  contains  an  artery,  vein,  and  lym- 
phatic (Schaffer).  In  this  manner  every  part  of  the  osseous 
substance  communicates. 

Development. — The  development  of  bone  is  effected  in  two 
ways:  (1)  from  cartilage,  the  intracartilaginous;  (2)  from 
membrane,  the  intramembranous ;  the  former  occurring  at  the 
base  of  the  skull  for  the  protection  of  vital  centers,  or  m  the 
extremities  to  secure  rigidity  of  the  parts. 

In  the  intracartilaginous  the  parts  are  first  formed  in 
cartilage  and  then  converted  into  bone.  The  process  is  as  fol- 
lows: The  cartilage  cells  at  the  "center  of  ossification"  become 
enlarged  and  arranged  in  rows.  The  cartilaginous  matrix  also 
increases  and  separates  the  cells.  Lime  salts  are  deposited  be- 
tween the  rows  of  cells,  inclosing  them  in  oblong  spaces  called 
primary  areola'.  - 

Blood-vessels  from  the  dee}}  or  osteogenic  layer  of  the  peri- 
osteum, carrying  numerous  osteoblasts  (bone-forming  cells) 
and  osteoclasts  (bone-absorbing  cells)  pass  into  the  area  of 
calcified  cartilage  (center  of  ossification).  The  osteoblasts  re- 
place the  calcified  cartilage,  which  is  absorbed,  with  new  bone, 
which  latter  is  absorbed  in  part  (tunneled)  by  the  osteoclasts  to 
form  the  medullary  spaces  or  marrow  cavity. 

■The  walls  of  the  spaces  are  gradually  thickened  by  suc- 
cessive layers  of  osteoblasts,  forming  lamellae  of  bone,  till  noth- 
ing remains  but  a  channel — the  Haversian  canal. 

The  perichondrium  having  been  in  the  mean  time  con- 
verted into  periosteum,  the  osteogenic,  or  vascular,  layer  of  this 
membrane  furnishes  a  layer  of  osteoblasts  that  form  enveloping, 
circumferential  layers  of  bone. 

Thus,  from  the  osteoblasts  all  the  structures  of  bone  are 
produced;  the  remains  of  a  group  of  cells  constitute  an  Haver- 
sian canal,  the  layers  deposited  by  them  and  the  adjacent  cells, 


OSTEOLOGY.  7 

the  lamella1,  and  the  isulated,  persistent  cells  (osteoblasts)  form 
the  contents  of  the  lacunae,  or  "true  bone-cells/'  with  their  nu- 
trient canaliculi  diverging  from  them. 

In  the  intramembranous  form  the  parts  are  first  formed  in 
membrane,  and  from  one  or  more  centers  of  ossification  lime 
salts  are  deposited  in  radiating  spiculae,  or  osteogenic  fibers,  in- 
closing the  osteoblasts. 

From  these  fibers  the  process  spreads,  and  vessels  from  the 
neighboring  parts  pass  into  it  and  form  Haversian  canals. 


Fig.  L 
Frontal    bone,    outer   surface. 


The  formation  of  the  lamella!  and  the  lacunae  is  essentially 
the  same  as  in  the  intracartilaginous,  and  in  most  bones  both 
processes  go  on  simultaneously. 

Ossification  appears  first  in  the  clavicle  and  inferior  maxilla 
(from  fifth  to  seventh  week)  and  last  in  the  pisiform  bone 
(twelfth  year).  The  epiphyses  ossify  from  birth  and  unite  from 
the  age  of  puberty  on  to  maturity,  in  reverse  order  to  the  ap- 
pearance of  ossification,  being  regulated,  apparently,  by  the 
direction  of  the  nutrient  artery  in  the  upper  extremity  toward 
the  elbow  and  in  the  lower  extremity  from  the  knee.  The  only 
exception  to  this  rule  ie  the  lower  end  of  the  fibula,  which  ossifies 
and  also  becomee  united  before  the  upper  (vide  Table  of  <K-ili 


8 


HUMAN    ANATOMY. 


cation).  In  bones  with  only  one  epiphysis  the  artery  is  directed 
toward  the  other  extremity. 

Growth  of  Bones. — Long  bones  grow  in  thickness  from  the 
periosteum  and  in  length  from  the  cartilage  between  the  epiph- 
yses and  the  shaft  near  the  extremities.  The  medullary  cavity 
is  at  first  solid  and  grows  by  absorption  of  the  cancellous  tissue 
by  the  giant  cells,  or  osteoblasts. 

Flat  bones  grow  in  thickness  from  the  periosteum  and  in 
surface  from  the  borders.  Short  bones  grow  from  the  center 
or  centers  of  ossification  in  all  directions. 

THE  CRANIAL  BONES. 

The  cranial  bones  are  eight  in  number : — 

1  Frontal,  2  Temporal, 

2  Parietal,  1   Sphenoid, 
1  Occipital,  1  Ethmoid. 

The  frontal  bone  (os  frontal e)  forms  the  anterior  por- 
tion of  the  cranium,  and  consists  of  two  portions,  a  vertical  or 
frontal  portion  and  a  horizontal  or  orbitonasal  portion. 

The  vertical  portion  consists  of  two  surfaces,  external  and 
internal. 

The  external  surface  {fades  frontalis)  is  convex,  and  pre- 
sents the  frontal  eminence  {tuber  frontale)  on  either  side  of  the 
median  line,  the  superciliary  ridges  (arcus  superciliaris)  pro- 
duced by  the  frontal,  sinuses,  beneath,  below  which  is  the 
supraorbital  arch  {mar go  supraorbitalis) ,  forming  the  upper 
boundary  of  the  orbit,  and  terminating  on  either  side  in  the 
external  angular  process  {processus  zygomaticus),  articulating 
with  the  malar  bone,  and  the  internal  angular  process,  articulat- 
ing with  the  lachrymal  bone,  and  having  at  its  inner  third  a 
notch  or  foramen,  the  supraorbital  foramen,  for  passage  of 
supraorbital  artery,  nerve  and  vein. 

Ascending  from  the  external  angular  process  is  the  tem- 
poral riclge  {Unea  temporalis)  for  attachment  of  temporal  fascia. 
Between  the  internal  angular  processes  is  the  nasal  notch,  for 
articulation  with  the  nasal  bone,  and  nasal  process  of  superior 
maxilla,  terminating  below  in  the  nasal  spine  {spina  nasalis  or 
frontalis)  ,  and  above  it  projects  the  nasal  eminence,  or  glabella, 
marking  the  location  of  the  frontal  sinuses. 

The  posterior  or  internal  surface  (cerebral  surface,  or 
fades  cerebralis)  is  concave  and  lodges  the  anterior  lobes  of 
the  brain. 


OSTEOLOGY. 


9 


In  the  median  line  is  the  frontal  crest  (crista  frontalis), 
which  gives  attachment  to  the  J'alx  cerebri  and  terminates  he- 
low  in  a  foramen,  the  foramen  caecum,  for  passage  of  a  small 
vein  from  the  nose  to  the  longitudinal  sinus.  The  crest  is 
grooved  for  longitudinal  sinus,  and  has  on  either  side  of  it 
depressions  for  the  Pacchionian  hodies.  This  surface  is  also 
grooved  for  anterior  meningeal  arteries. 

The  horizontal  portion  or  orbital  portion  (pars  orbitalis) 
consists  of  an  external  and  internal  (cerehral  surface,  fades 
cerehralix)    surface. 


vitA  Sup.MaxiU 


FrontaX    Si%u* 

I Ko-jm ndtd  6tu«   »f  Xrual  SpVTtPf 
J^rmin.j  p*H  tf  jfcf   tf    Rett 


Pig.  2. 
Frontal   bone,   inner  surface. 

The  external  surface  (fades  orbitalis)  is  concave,  to  form 
the  roof  of  the  orbit,  and  separated  from  the  opposite  side  by 
tin-  ethmoidal  notch. 

To  the  outer  side  is  a  deep  depression  for  the  lachrymal 
gland,  the  Lachrymal  fossa  (fossa  glandula  lacrimalis) ,  and  to 
the  inner  side  a  slight  one,  the  trochlear  fossa  (fovea  tro- 
chlearis),  for  the  pulley  of  superior  oblique. 

On  the  margin  of  the  orbital  plate  are  two  notches  con- 
verted into  foramina  by  articulation  with  the  ethmoid,  the  an- 
terior ethmoidal  canal  (foramen,  ethmoidal e  anterius),  for 
passage  of  nasal  nerve  and  anterior  ethmoidal  vessels,  and  the 
posterior  ethmoidal  canal  (foramen  ethmoidals  postervus),  for 
passage  of  posterior  ethmoidal  vessels. 


10 


HUMAN    ANATOMY. 


The  internal  surface  is  marked  by  the  convolutions  of  the 
anterior  lobes  of  the  brain. 

Between  the  two  plates  of  the  vertebral  portion  are  the 
frontal  sinuses,  two  irregular  cavities  lined  with  mucous:  mem- 
brane and  opening  into  the  middle  meatus  of  the  nose  on  either 
side  by  the  infunclibulum  (infundibulum  ethmoidal e). 

It  articulates  with  twelve  bones:  two  parietal,  sphenoid, 
ethmoid,  nasal,  superior  maxillary,  lachrymal,  and  malar. 


%§$0^ 


Fig.  3. 
Parietal   bone,   outer  surface. 


Its  muscular  attachments  are  three  pairs :  corrugator  super- 
cilii,  orbicularis  palpebrarum,  and  temporal. 

It  is.  developed  from  membrane  by  two  ossific  centers,  one 
for  each  lateral  half. 

Parietals  (os  parietale). — These  are  two  quadrilateral 
bones  forming  the  superior  and  lateral  walls  of  the  cranium. 
Each  bone  consists  of  two  surfaces,  four  borders,  and  four 
angles. 

The  external  surface  (fades  parietalis)  is  convex  and  pre- 
sents the  parietal  eminence  (tuber  parietale)  "a  little  above  the 
middle,  marking  the  original  center  of  ossification,  the  temporal 
ridge  (linea  temporalis) ,  crossing  about  the  center  for  attach- 
ment of  the  temporal  fascia,  and  the  parietal  foramen  (foramen 


OSTEOLOGY 


11 


parietdle),  near  the  superior  border  or  sagittal  suture,  for  pass- 
a  vein,  the  emissary  vein  of  Santorini,  to  the  longi- 
tudinal sinus. 

The  internal  surface  or  cerebral  surface  (fades  cerebralis) 
is  concave,  and  presents  furroivs  for  the  branches  of  the  menin- 
geal arteries,  depressions  |  foveolce  granulares  \  Pacchioni]  )  foT 
cerebral  convolutions,  and   Pacchionian  bodies. 

A  half-groove  (sulcus  sagittalis)  along  the  superior  border 
for  longitudinal  sinus,  and 


Anal* 


\  A*t.  Sup. 


AniTiifcnXnyle 


FlO.    4. 
Parietal   bone,    inner  surface. 


A  groove  (sulcus  transversus)  near  the  posterior  inferior 
angle  for  the  lateral  sinus. 

The  superior  border  or  sagittal  margin  (margo  sagittalis) 
articulates  with  its  fellow  of  the  opposite  side,  forming  the 
Bagittal  suture; 

The  inferior  border — also  called  the  squamous  margin 
(margo  squamosus) — articulates  from  before  backward  with  the 
sphenoid,  squamous  and  mastoid  portions  of  temporal  bonee ; 

The  anterior  border  -also  called  frontal  margin  (margo 
frontalis) — forms  with  the  frontal  hone  the  coronal  suture,  and 

The  posterior  border  or  occipital  margin  (margo  occip- 
italis)   form-   with   the  occipital    hone   the   lainhdoid   suture. 


12 


HUMAN   ANATOMY. 


Of  the  angles,  the  anterior  inferior  (angulus  sphenoidalis) 
is  the  only  important  one,  being  longer  and  grooved  internally 
by  the  middle  meningeal  artery. 

It  articulates  with  five  bones — frontal,  sphenoid,  temporal, 
occipital,  and  opposite  parietal  bones. 

It  has  but  one  muscle  attached — the  temporal. 

It  is  developed  from  an  ossific  center. 

The  occipital  bone  (os  occipitalis)  forms  the  posterior 
inferior  portion  of  the  cranium.  It  presents  two  surfaces,  four 
angles-,  and  four  borders. 


Fig.  5. 
Occipital   bone,   outer  surface. 


The  external  and  posterior  surface  is  irregularly  convex, 
and  presents 

The  occipital  protuberance  or  inion  (protuherantia  occip- 
italis externa),  for  insertion  of  ligamentum  nucha,  descending 
from  which  to  the  foramen  magnum  is 

The  occipital  crest  {crista  occipitalis  externa)  for  tendin- 
ous attachment,  and  diverging  on  either  side,  above  and  below, 
are 

The  superior  curved  or  superior  nuchal  line  (linea  nuchte 
suprcema)  for  attachment  of  occipitofrontalis,  trapezius,  and 
other  muscles;  and 


OSTEOLOGY 


13 


The  inferior  curved  or  interior  nuchal  line  (linea  nucha' 
inferior)  for  attachment  of  rectus  capitis  posticus,  major  and 
minor. 

Anteriorly  it  presents  a  large  aperture, 

The  foramen  magnum  (foramen  occipiMe  magnum),  trans- 
mitting the  medulla  oblongata  and  its  coverings,  the  vertebral 
arteries,  and  the  spinal  accessory  nerves. 

On  either  side  of  the  foramen  magnum  are  the  condvlic  or 
lateral  portions    (paries  laterales)    hearing  the  condyles    (con- 


Sufierier  Ati^lt 


J»f'r,J  A„slf  V*V 


Fig.  6. 
Occipital  bone,   inner  surface. 


dylus  occipitalis)  for  articulation  with  the  atlas,  the  inner  bor- 
deT  of  each  condyle  presenting  a  tubercle  for  the  check  liga- 
ment. 

Externally  to  each  condyle  are  the  jugular  processes 
(processus  jugularis)  affording  attachment  for  the  rectus  capitis 
lateralis,  and  forming  by  its  articulation  with  the  fibrous  portion 
.,('  ihc  temporal  bone  the  jugular  foramen,  or  foramen  lacerum 
posterius,  transmitting  the  internal  jugular  vein,  glossopharyn- 
geal, pneumogastric  and  spinal  accessory  nerve-,  and  menin- 
geal branches  of  the  ascending  pharyngeal  and  occipital  arteries. 

In  front  of  the  condyles  on  either  side  are  the  openings  of 


14-  .  HUMAN    ANATOMY. 

the  anterior  condyloid  foramen  (canalis  hypoglossi),  for  pass- 
age of  hypoglossal  nerve  and  meningeal  branch  from  the 
ascending  rmaryngeal  artery;  and  behind,  the  posterior  con- 
dyloid foramen  (canalis  condyloideus) ,  for  passage  of  a  small 
vein  to  the  lateral  sinus. 

In  front  of  the  foramen  magnum  is  the  basilar  process 
(pars  basilaris),  articulating  with  the  sphenoid  bone,  and 
grooved  on  its  under  surface  by  the  pharyngeal  spine  (tuber- 
culum  pliaryngeum)  for  the  insertion  of  the  tendinous  raphe 
and  superior  constrictor  of  the  pharynx. 

The  internal  or  cerebral  surface  is  irregularly  concave  and 
divided  by  a  crucial  ridge,  or  occipital  cross,  into  four  fossae, 
the  upper,  for  the  posterior  lobes  of  the  cerebrum,  and  the  lower, 
for  the  lateral  lobes  of  the  cerebellum.  Its  center  is  marked  by 
an  eminence,  the  internal  occipital  protuberance  (protuberantia 
occipitalis  interna),  which  is  hollowed  out  to  correspond  to  the 
torcular  Herophili,  or  confluence  of  the  sinuses. 

The  upper  division  of  the  crucial  ridge  affords  attachment 
for  the  falx  cerebri,  being  grooved  for  the  great  longitudinal 
sinus;  the  lower  extremity,  called  also  the  internal  occipital 
crest  (crista  occipitalis  interna),  affords  attachment  for  the  falx 
cerebelli,  being  grooved  for  the  occipital  sinus;  and  the  lateral 
divisions  afford  attachment  for  the  tentorium  cerebelli  and  are 
grooved  for  the  lateral  sinuses. 

The  internal  surfaces  of  the  jugular  processes  are  grooved 
for  the  lateral  sinuses. 

In  front  of  the  foramen  magnum  is  the  basilar  groove 
(clivus)  lodging  the  medulla  oblongata  and  part  of 'the  pons 
Varolii.  Its  lateral  borders  (the  basilar  process)  are  grooved 
(sulcus  petrosus  inferior)  for  the  inferior  petrosal  sinus. 

The  superior  angle  articulates  with  the  parietal  bones,  the 
inferior  angle  articulates  with  the  sphenoid,  and  the  lateral 
angles  are  wedged  in  between  the  mastoid  portion  of  the  tem- 
poral and  the  posterior  inferior  angle  of  the  parietal. 

This  bone  has  four  foramina — foramen  magnum,  anterior 
and  posterior  condyloid,  and  foramen  lacerum  posterius. 

It  articulates  with  six  bones — two  parietal,  two  temporal, 
the  sphenoid  and  the  atlas. 

The  muscular  attachments  are  twelve  (12)  :  occipitofron- 
talis,  trapezius,  sternomastoid,  complexus,  splenitis  capitis,  ob- 
liquus  superior,  rectus  capitis  posticus  major  and  minor,  rectus 
lateralis,  rectus  antieus  major  and  minor  and  constrictor 
pharyngis  superior. 

It  is  developed    from  seven    (7)    ossific  centers:    four  for 


OSTEOID  h,y 


15 


the  tabular,  or  supraoccipital,  or  occipital  portion  proper;  one 
for  each  condyloid,  or  external  occipital  portion,  and  one  for  the 
basilar,  or  basioccipital  port  ion. 

Temporals  (os  temporale). — These  are  situated  at  the  side 
and  base  of  the  cranium,  and  consist  of  three  portions — the 
squamous,  mastoid  and  petrous. 

The  squamous  portion  (squama  temporalis)  is  scale-like, 
and  overlaps  the  parietal  bone.  Its  external  surface  (fades 
temporalis),  convex  behind,  concave  in  front,  presents  from  be- 
fore backward  the  following: — 


Fig.  7. 
Left  temporal   bone,   outer  surface. 

The  zygoma,  or  zygomatic  process  (processus  zygomaticus), 
an  arched  process  of  bone  articulating  with  the  zygomatic  proc- 
ess of  til.-  malar  bone,  affording  attachment  above  to  the 
temporal  fascia  and  below  to  the  masseter  muscle.  It  is  con- 
nected  to  the  body  of  the  bone  by  three  roots,  the  anterior  root 
of  which  ends  in  the  eminentia  articularis  (tuberculum  arhc- 
idare),  a  process  of  bone  in  front  of  the  glenoid  cavity,  and 
presents  »i  its  junction  a  tubercle  for  the  external  lateral  liga- 
ment; the  middle  root,  also  called  the  postglenoid  process  or 
tubercle,  terminates  at  the  Glaserian  fissure  (fissura  petro- 
tympanic [Glasen]),  and  the  posterior  root  forma  the  posterior 
portion  of  temporal  ridge  and  gives  attachment  to  the  retrahens 
aurem, 


16 


HUMAN    ANATOMY. 


The  glenoid  fossa  (mandibular)  is  a  marked  depression 
hollowed  out  for  articulation  of  the  condyle  of  the  lower  jaw. 
It  is  bounded  in  front  by  the  eminentia  articularis,  to  the  outer 
side  by  the  middle  root,  and  behind  by  the  vaginal  process 
(vagina  processus  styloidei).  It  is  divided  into  two  portions  by 
the  Glaserian  fissure,  the  anterior  being  separated  from  the 
auditory  process  by  the  postglenoid  tubercle — rudimentary  in 
man — and  the  posterior  being  formed  by  the  tympanic  plate,  a 
thin  plate  of  bone  forming  the  front  wall  of  the  tympanum. 


Beprcenun  far  Dara-malrr 
BtaBUfi  AueUtvrutM  vntnnvu* 


"n,i      (Jr«»6  ... 

'E-miwute for  Superior  J£mc/v^tra^lar  t«aw 
^\^*  Hiatus  FaUopil 
^  ^^Ojicnijui  for  SitfaMer  Pctross&lforif* 

Dcnresaum  far  Cwstert^an   gaitglum 

UrutU  vasztd  Uu-ouyh  Caraud  OiMal 


Fig.  8. 
Left  temporal  bone,   inner  surface. 


The  Glaserian  fissure  communicates  with  the  tympanum, 
transmits  the  tympanic  branch  of  the  internal  maxillary  artery, 
and  lodges  the  processus  gracilis  of  the  malleus. 

In  the  angle  between  the  squamous  and  petrous  portions  the 
chorda  tympani  nerve  passes  from  the  tympanum  through  the 
canal  of  Huguier  (canaliculus  clwrdce  tympani). 

The  internal  surface  (cerebral  surface,  fades  cereoralis)  of 
the  squamous  portion  presents  the  markings  of  the  convolu- 
tions, and  grooves  for  the  ramifications  of  the  middle  meningeal 
artery.  The  mastoid  portion  (pars  mastoidea)  is  convex,  rough, 
and  nipple-like,  and  presents,  externally,  the  following: — 

The  mastoid  foramen  (foramen  mastoideum)  near  the  pos- 


OSTEOLOGY. 


17 


terior  border,  transmits  a  branch  of  the  occipital  artery  to  the 
dura  mater  and  a  small  vein  to  the  lateral  sinus; 

The  mastoid  process  (processus  mastoideus) ,  a  prominent 
projection,  composed  of  the  mastoid  cells  (celluke  mastoid ew) , 
and  affording  insertion  for  the  splenitis  capitis,  stemomastoid 
and  trachelomastoid  muscles. 

To  its  inner  side  is  a  groove,  the  digastric  groove,  also 
called  digastric  fossa   (incisura  mastoidal),  for  attachment  of 


(TYLO-PMAKYNOCOt 


Rough  Quadrilateral 'Sulfate 
Vpt^una  of  carotid  cm,ol 
Canaljbr  Jacobxon't  nerx't 
Anus/bic.rus  Corhlatz 
Canal  for  Arnold'*  nerve 
Jvg>u7ar  fuasa 
Vagi  naT  jjroceti 
Styloid  prueeet 
jStylo-'masroi-a7  foramen 
Jxiavlnr  Si'rfaee 
Auricular  future 


FIG.   9. 
Left  temporal   bone,    inferior  surface  of  the  petrous  portion. 


the  digastric  muscle,  and  still  more  internally  the  occipital 
groove  (sulcus  a.  occipitalis)  for  the  accommodation  of  the 
occipital  artery. 

The  internal  surface  is  concave,  and  presents  a  groove,  the 
fossa  ngmoidea  (sulcus  si'jmoideus)  for  the  lateral  sinus,  in  the 
bottom  of  which  is  the  opening  of  the  mastoid  foramen  (foramen 
mastoideum ) . 

The  petrous  portion  (pars  petrosa  pyramis)  is  pyramidal 
in  shape,  intensely  hard,  and  contains  the  internal  ear.     It  pro- 

2 


18 


HUMAN    ANATOMY. 


jects  downward,  forward  and  inward,  and  presents  for  exami- 
nation a  superior,  posterior  and  inferior  surface. 

The  superior  or  anterior  surface  (fades  anterior  pyramidis) 
is  united  to  the  squamous  portion  by  the  temporal  suture  and 
presents  the  following- : — 

An  eminence  (eminentia  arcuata),  marking  the  position  of 
the  superior  semicircular  canal; 

A  depression,  forming  the  roof  of  the  tympanum; 

The  hiatus  Fallopii  (hiatus  canalis  facialis),  transmitting 
a  branch  of  the  middle  meningeal  artery  and  the  petrosal  branch 
of  the  A^idian  nerve  to  the  aqueduct  of  Fallopius; 

Foramen  (apertura  superior  canaliculi  tympanici)  for  the 
smaller  petrosal  nerve; 

Orifice  of  the  carotid  canal,  transmitting  the  carotid  plexus 
of  the  sympathetic  and  the  internal  carotid  artery;  and 

Depression  (impressio  trigemini)  for  Gasserian  ganglion 
of  the  trifacial  nerve. 

The  posterior  surface  (fades  posterior  pyramidis)  presents 
about  its  middle 

The  meatus  auditorius  internus  (meatus  acusticus  inter- 
ims), at  the  bottom  of  which  is  the  lamina  cribrosa,  a  perpendic- 
ular plate  of  bone,  and  numerous  foramina  for  the  exit  of  the 
auditory  nerve  and  the  auditory  branch  of  the  basilar  artery, 
one  of  which  is  the  commencement  of  the  aquaeductus  Fallopii 
(canalis  facialis)  for  the  facial  nerve. 

Posteriorly  to  the  internal  meatus  is  the  aquaductus  ves- 
tibidi,  lodging  a  process  of  dura  mater,  and  transmitting  an 
artery  and  vein,  and  between  them  another  small  depression  for" 
the  same  purpose. 

The  inferior  or  basilar  surface  (fades  inferior  pyramidis) 
presents,  from  within  outward,  the  following : — 

A  rough,  quadrilateral  surface,  for  attachment  of  the  tensor 
tympani  and  levator  palati  muscles; 

The  opening  of  the  carotid  canal  (foramen  caroticum  ex- 
ternum), transmitting  the  carotid  plexus  of  the  sympathetic 
and  the  internal  carotid  artery; 

Aqiuzductus  cochlece  (apertura  externa  canaliculi  cochlea), 
transmitting  a  vein  to  the  internal  jugular  vein  from  the 
cochlea ; 

Jugular  fossa  (fossa  jugularis),  forming  the  jugular  fora- 
men (foramen  lacerum  posterius)  by  articulation  with  the 
occipital  bone,  and  transmitting  the  internal  jugular  vein,  the 
glossopharyngeal,   pneumogastric,   and   spinal   accessory  nerves. 


OSTEOID  >GY. 


19 


and  meningeal  branches  "J'  the  ascending  pharyngeal  and  occip- 
ital aiter   -  . 

Foramen  for  Jacobsons  nerve,  the  tympanic  branch  of  the 
_    ssopharyngeal  (ft.  tympanicus) ; 

Foramen  for  entrance  of  Arnold's  nerve,  the  auricular 
branch  of  the  pneumogastric ; 

Jugular  surface  for  articulation  with  jugular  process  on  oc- 
cipital bone ; 

The  vaginal  process  (vagina  processus  styloidea),  extend- 
ing from  the  mastoid  process  to  the  carotid  canal,  and  ensheath- 
ing 


Fig.  10. 

Section  of  the  temporal  bone  (natural  size)  through  the  middle 
<-ar.  Fallopian  canal,  mastoid  antrum,  and  cells,  showing  dense  bone 
between  the  antrum  and  cells,  with  no  communication  between  them: 
1,  drumhead:  L'.  tip  of  the  mallet  handle;  3,  anvil,  showing  the  long 
crus  at  the  right  for  articulation  with  the  stirrup,  and  the  short  proc- 
t  the  left  which  serves  the  purpose  of  an  anchor  to  the  bone;  4, 
head  of  the  mallet;  '■>.  tensor  tympani  muscle  and  tendon;  6,  dense 
bone  where  pneumatic  spaces  are  usually  found;  7,  pneumatic  cells  in 
the  tip  of  the  mastoid  process:  8,  Fallopian  canal,  for  the  facial  nerve; 
9,  the  Btirrup.  At  the  right  of  9  and  at  the  left  of  the  anvil  is  the 
aditus  ad  antrum,   connecting  the  tympanum  with  the  antrum. 


The   styloid    process    (processus  styloideus),   affording  at- 

lacluiiciit    for  the  stylomaxillary  and  stylohyoid   ligaments  and 

bylohyoideus,    stylopharyngeus    and    styloglossus    muscles; 

The  stylomastoid  foramen  (foramen  stylomasioideum) ,  for 
exit  of  facial  nerve; 

The  auricular  fissure  (fissura  tympanomastoidea) ,  for  the 
exil   of  Arnold's   aerve,   the  auricular  branch   of  the   pneumo- 

ric. 

The  base  of  the  petrous  port ion  presents 

The-  external  auditory  meatus  (meatus  acusticus  externus), 

•  anal  leading  into  the  t) mpanum,  and 


20  HUMAN    ANATOMY. 

The  auditory  process,  a  lamina  of  bone  forming  the  greater 
part  of  its  walls. 

Borders. — The  superior  border  (angulus  superior  pyram- 
idis)  affords  attachment  to  the  tentorium  cerebelli,  and  has  a 
groove  for  the  superior  petrosal  sinus.  The  posterior  border 
{angulus  posterior  pyramidis)  forms  part  of  the  jugular  fossa 
(fossa  jugularis).  The  anterior  border  (angulus  anterior  py- 
ramidis) articulates  with  the  spinous  process  of  the  sphenoid. 
Between  the  squamous  and  petrous  portions  may  be  seen  the 
opening  of  the  canalis  musculotubarius;  this  canal  is  found 
either  completely  or  partially  divided  by  an  osseous  lamina, 
separated  by  the  processus  cochleariformis  (septum  canalis  mus- 
cuiotuharii),  for  the  tensor  tympani  muscle  above  and  the 
Eustachian  tube  below. 

Muscular  attachments  are  fifteen: — 

To  the  squamous  portion,  2 — the  temporal  and  masseter; 
to  the  mastoid  portion,  6 — -sternomastoid,  occipitofrontal!?, 
splenitis  capitis,  trachelornastoid,  retrahens  aurem,  and  digas- 
tricus;  to  the  styloid  portion,  3— stylohyoideus,  stylopharyn- 
geus  and  styloglossus;  and  to  the  petrous  portion,  4 — levator 
palati,  tensor  palati,  tensor  tympani  and  stapedius. 

Its  ossific  centers  are  ten  (10),  1  for  the  squamous  portion, 
including  the  zygoma,  1  for  auditory  process,  6  for'  petrous  and 
mastoid  portions,  and  2  for  the  styloid  process. 

The  sphenoid  (os  sphenoidale)  is  wedged  in  between  the 
bones  at  the  base  of  the  skull  anteriorly  and  resembles  a  bat 
with  extended  wings.     It  consists  of 

A  body,  2  Lesser  wings,   and 

2  Greater  wings,  2  Pterygoid    processes. 

It  presents 

12  Foramina,  12  Pairs  of  muscles,  and 

12  Articulations,  14  Centers   of   ossification, 

and  is  in  every  respect  the  most  important  bone  of  the  cranium, 
entering  into  the  formation  of 

5  Cavities —  (2)    Zygomatic, 

(1)  Anterior  cerebral,  (3)    Sphenomaxillary, 

(2)  Middle  cerebral,  (4)    Nasal,  and 

(3)  Orbital,  3  Fissures — 

.(4)   Pharyngeal,  (1)  Sphenomaxillary, 

(5)   Nasal,  (2)'  Pterygomaxillary,  and 

4  Fossce —  (3)  Sphenoidal     or     foramen 
( 1 )   Temporal,  lacerum  anterior. 


OSTEOLOCY. 


21 


The  body  (corpus)  is  a  hollow  cube  and  presents  upper, 
lower,  anterior  and  posterior  surfaces. 

The  upper  surface  (fades  cerebralis)  of  the  body  presents 
from  before  backward  the  following  points: — 

Ethmoidal  spine  (s/rina  ethmoidalis) ,  for  articulation  with 
the  cribriform  plate  of  the  ethmoid ; 

Optic  groove  (sulcus  chiasmal  is),  lodging  the  optic  com- 
missure and  terminating  in  the  optic  foramen; 

Olivary  process  (iuuerculum  sella'),  a  small,  olive-like 
eminence  behind  the  optic  groove; 

Pituitary  fossa  or  sella  turcica  (fossa  hypohyseos),  for  the 
pituitary  body; 

tliidlt   Ck^ld  prxcj 

P^/CTzrr  CUiwutprocCM  \         •M™^  •T/'W 
~"-^_^^_^  **  \ ,  \      Groove  jar 


Fig.  11. 
Sphenoid  bone,   upper  surface. 


Middle  clinoid  processes  (processus  dinoidei  medii),  one 
on  either  side  bounding  the  pituitary   fossa; 

Dorsum  sella,  or  dorsum  ephippii,  a  quadrilateral  plate  of 
bone,  bounding  the  pituitary  fossa  behind,  and  notched  on  either 
side  for  the  passage  of  the  sixth  cranial  nerves; 

Posterior  clinoid  processes  (processus  clinoideus  posterior) 
are  the  terminations  of  the  dorsum  sella1  on  either  side  and 
afford  attachment  to  the  tentorium  cerebelli; 

Declivity,  or  clivus  Blumenbachii  (clivus),  supporting  the 
upper  part  of  the  pons  Varolii; 

Carotid  or  cavernous  groove  (sulcus  caroticus),  lodging  the 
cavernous  -inns  and  the  internal  carotid  artery; 

Lingula  (lingtUa  sphenoidalis) ,  a  ridge  of  bone  to  the  outer 
side  of  the  cavernous  sinus. 


22 


HUMAN    ANATOMY. 


The  lower  surface  presents : — 

Rostrum  {rostrum  sphenoidalis) ,  the  continuation  down- 
ward of  the  ethmoidal  crest,  for  articulation  with  the  ala?  of 
the  vomer; 

Vaginal  processes,  a  thin  plate  of  hone  on  either  side  artic- 
ulating with  the  edges  of  the  vomer;  and 

Groove  (sulcus  pterygopalatinus),  converted  into  the 
pterygopalatine  canal  by  articulation  with  the  sphenoidal 
process  of  the  palate  bone  for  transmission  of  the  pharyngeal 
nerve  and  pterygopalatine  vessels. 


Jtery>joid  R 


LAXATOR    TYMPANI 


Internal  Pterygoid,  yilate 

HumuJxi.r    Uroctst 


Fig.  12. 
Sphenoid  bone,   anterior  surface. 


The  anterior  surface  presents : — 

Ethmoidal  crest  or  sphenoidal  crest  (crista  sphenoidalis), 
a  thin  plate  of  bone  articulating  with  the  ethmoid; 

Openings  of  sphenoidal  cells  or  sinuses  (sinus  sphenoidal 'es) 
partially  closed  by  the  sphenoidal  turbinated  bones  or  pyramids 
of  Wistar  (conchce  sphenoid  ales),  two  curved  plates  of  bone  ab- 
sent in  infancy,  but  derived  as  a  pair  of  cones  from  the  ethmoid; 
The  sphenoidal  cells  open  into  the  superior  meatus  of  the  nose, 
but  occasionally  into  the  posterior  ethmoidal  sinuses. 

The  posterior  surface  articulates  with  the  basilar  process  of 
the  occipital  and  becomes  united  to  it  between  the  eighteenth 
and  twenty-fifth  year. 


OSTEOLOGY.  23 

GEEATEK  OR  TEMPORAL  WINGS  OF  THE  SPHENOID 
(AL.K  MAiiX.E). 

The  superior  surfaces  (facie*  cerebralis)  of  the  great  wing, 
deeply  concave,  forms  part  of  middle  fossa  of  skull,  and  pre- 
sents the  following : — 

Foramen  rot  and  urn,  for  second  division  of  fifth  nerve;  fora- 
men ocale,  for  third  division  of  fifth,  small  meningeal  artery, 
and  small  petrosal  nerve;  foramen  Vesalii,  for  small  vein,  and 
foramen  spinosum,  for  passage  of  middle  meningeal  artery. 

The  exterior  surface  is  convex  and  presents: — 

Pterygoid  ridge  or  infratemporal  crest  (crista  infratem- 
poral^), dividing  the  hone  into  two  portions; 

Spinous  process,  for  attachment  of  tensor  palati  muscle,  and 
the  internal  lateral  ligament  of  the  lower  jaw. 

The  anterior  or  orbital  surface  (fades  orbitalis)  enters  into 
the  formation  of  the  orbit  and  presents  numerous  external 
orbital  foramina  for  passage  of  branches  of  the  deep  temporal 
arteries. 

The  circumference  of  the  greater  wing  forms  part  of  the 
sphenoidal  fissure  and  articulates  with  the  frontal  bone  in  front 
and  laterally  with  the  parietal,  squamous  and  petrous  portions 
of  the  temporal  bone. 

The  lesser  or  orbital  wings  (alee  parvce),  or  processes  of 
Ingrassias,  project  on  either  side  from  the  superior  surface  of 
the  body,  to  which  they  are  attached  by  two  roots. 

The  upper  surface  forms  part  of  the  anterior  fossa  of  the 
skull.  The  lower  surface  forms  part  of  the  orbit  and  the  upper 
border  of  the  sphenoidal  fissure,  or  foramen  lacerum  anterius 
{fissiira  orbitalis  superior),  transmitting  the  third",  fourth  and 
ophthalmic  divisions  of  the  fifth  and  the  sixth  cranial  nerve, 
orbital  branch  of  the  middle  meningeal  artery,  a  recurrent 
branch  of  the  lachrymal  artery,  the  ophthalmic  vein,  and  fila- 
ment- from  the  cavernous  plexus. 

The  anterior  clinoid  process  (processus  clinoideus  anterior) 
i-  formed  by  the  inner  extremity  of  the  posterior  border. 

Between  the  two  roots  is  the  optic  foramen  (foramen 
opticum),  transmitting  the  optic  nerve  and  ophthalmic  artery. 

The  pterygoid  processes  (processus  pterygoidei)  are  two 
wing-like  processes  descending  from  the  junction  of  the  greater 
wings  with  the  body. 

Each  process  presents  the  following:  — 

An    externa]     pterygoid     plate     (luminu     lateralis    processus 

pterygoidei)}  for  attachment  oi  the  external  pterygoid  muscle; 


g4  HUMAN    ANATOMY. 

The  pterygoid  fossa  (fossa  pterygoidei)  lies  between  the 
two  plates  and  affords  attachment  for  the  internal  pterygoid 
muscle. 

The  internal  pterygoid  plate  (lamina  medialis  processus 
pterygoidei),  terminating  below  in  a  hook-like  process — the 
hamular  process  (hamulus  pterygoideus) — for  the  tendon  of  the 
tensor  palati  nrascle. 

The  scaphoid  fossa  (fossa  scaphoid  ea) ,  at  the  base  of  the 
internal  plate,  affording  origin  for  the  tensor  palati  muscle  and 
presenting  just  above  it,  the  posterior  opening  of  the  Vidian 
canal  (canalis  pterygoideus  [Vidii])  for  the  Vidian  vessels  and 
nerves. 

An  angular  interval  between  the  two  plates  articulates  with 
tuberosity  or  pterygoid  process  of  the  palate  bone. 

The  foramina  are:  Opticum,  lacerum  anterius,  rotundum, 
Vesalii,  ovale,  spinosum,  and  two  canals — Vidian  and  pterygo- 
palatine; articulates  with  twelve  bones — two  malar,  two  palate, 
vomer,  and  all  of  cranium.  Its  muscular  attachments  are 
eleven  pairs — external  and  internal  pterygoid,  temporal,  tensor 
palati,  superior  constrictor,  levator  palpebral,  obliquus  superior; 
superior,  inferior,  internal  and  external  recti.  Its  ossific  cen- 
ters are  fourteen,  as  follows:  Body,  2  anterior  and  2  posterior; 
external  pterygoid  plates  and  greater  wings,  2 ;  internal  ptery- 
goid plates,  2;  lingula,  2;  lesser  Avings,  2;  sphenoturbinals,  2. 

The  ethmoid  (os  etlimoidale)  is  a  spongy,  cubical  bone, 
consisting  of  a  perpendicular  lamella,  a  horizontal  or  cribri- 
form, plate,  and  two  lateral  masses. 

The  horizontal  or  cribriform  plate  (lamina  cribrosa)  pre- 
sents from  before  backward  the  following  points: — 

Two  projections  (processus  alares)  completing  the  foramen 
coBCum,  the  commencement  of  the  longitudinal  sinus; 

Crista  galli,  affording  attachment  to  the  falx  cerebri; 

Foramina  cribrosa,  three  rows,  transmitting  filaments  of 
the  olfactory  body; 

Fissure  for  passage  of  the  nasal  branch  of  the  ophthalmic 
nerve. 

The  perpendicular  plate  (lamina  perpendicularis,  or  mes- 
ethmoid)  assists  in  forming  the  nasal  septum,  articulating  in 
front  with  the  crest  of  the  nasal  bones  and  the  frontal  bone  and 
behind  with  the  sphenoid  and  vomer.  It  is  usually  inclined 
to  one  side. 

The  lateral  masses — labyrinth  (labyrinthus  etlimoidalis)  — 
are  composed  of  the  ethmoidal  cells. 


OSTEOLOGY. 


The  upper  surface  presents  two  notches,  converted  into  fo- 
ramina by  articulation  with  the  frontal  bone — 

The  anterior  ethmoidal  foramen  (caimUs  ethmoidalis  an- 
teriiis),  transmitting  the  anterior  ethmoidal  artery  and  nasal 
nerve,  and 

The  posterior  ethmoidal  foramen  (canalis  ethmoidalis  pos- 
terius),  transmitting  the  posterior  ethmoidal  artery  and  vein. 

The  outer  surface  presents 

The  os  phi  mi  tit  (lamina  papi/racea),  a  smooth  plate  of  bone 
forming  the  inner  wall  of  the  orbit,  and  projecting  downward 
from  it  is 


toitk   mf.'turbinateJ  6. 

Fig.  13. 
Ethmoid  bone. 

The  unciform  process  (processus  uncinatus),  a  hook-like 
plate  of  bone  closing  the  upper  part  of  the  opening  of  the 
antrum. 

The  inner  surface  forms  part  of  the  nasal  fossa,  and  presents 

The  superior  turbinated  bone  (concha  nasalis  superior), 
forming  the  upper  boundary  of  the  superior  meatus  (meatus 
nasi  superior),  into  which  open  the  sphenoidal  and  posterior 
ethmoidal  cell-,  and  the 

.Middle  turbinated  bone  or  the  inferior  ethmoidal  turbinate 
bone  (concha  nasalis  media),  forming  the  upper  boundary  of 
the  middle  meatus  of  the  nose,  into  which  open  the  anterior 
ethmoidal  cells,  the  frontal  cells  through  the  infundibulum 
(infundihuluni  ethmoidale)  and  the  antrum  Eighmorianum 
|   imi.s  in n. i  iHuris). 


26  HUMAN   ANATOMY. 

It  articulates  with  fifteen  bones — -two  sphenoidal  turbinated, 
sphenoid,  frontal,  and  eleven  of  the  face,  the  two  nasal,  two 
lachrymal,  two  superior  maxilla?,  two  palate,  two  inferior  turbi- 
nated and  the  vomer. 

It  has  no  muscular  attachments. 

Its  ossific  centers  are  three — one  for  the  lamella  and  one  for 
each  lateral  mass. 

BONES  OF  THE  EACE    (OSSA  FACIEI). 

The  bones  of  the  face  are  fourteen  in  number — six  pairs  and 
two  single  bones:    Two  lachrymal,  two  nasal,  two  malar,  two 


viihFrontdl 


Fig.  14. 
Lachrymal  bone. 

superior  maxillary,  two  palate,  two  turbinal,  one  vomer  and  one 
inferior  maxillary. 

The  lachrymal  (os  lacrimale)  are  two  small,  thin  bones 
forming  part  of  the  inner  wall  of  the  orbit  and  the  lachrymo- 
nasal  duct,  and  named,  from  their  resemblance  to  a  finger-nail, 
the  ossa"  unguis. 

Each  presents  externally  : — 

The  lachrymal  crest  (crista  lacrimdlis  posterior)  affords 
attachment  for  the  tensor  tarsi  and  separates  the  anterior  sur- 
face from  the  groove; 

The  groove  forms  part  of  the  lachrymal  groove  and  lodges 
the  lachrymal  sac; 

The  hamular  process  (hamulus  lacrimalis),  or,  when  sep- 
arate, called  the  lesser  lachrymal  bone,  projects  downward  and 
articulates  with  the  lachrymal  tubercle  of  the  superior  maxilla. 


OSTEOLOGY 


v; 


Internally : — 

A  furrow,  corresponding  to  the  lachrymal  crest  on  the  ex- 
ternal surface ; 

The  internal  surface  enters  into  the  formation  of  the  middle 
meatus,  closing  in  the  anterior  ethmoidal  cells. 

It  articulates  with  four  bones — the  frontal,  ethmoid,  supe- 
rior maxilla  and  inferior  turbinated. 

The  only  muscular  attachment  is  the  tensor  tarsi. 

It   is  developed    from  one  ossific  center. 

The  nasal  hones  (ossa  nasalia)  are  two  irregularly  quad- 
rate bones  forming  together  the  bridge  of  the  misc. 

The  outer  surface,  covered  by  the  compressor  nasi  and  pyr- 
amidalis  nasi  muscles,  presents 

A  foramen  (foramen  nasale),  transmitting  a  small  vein. 

The  inner  surface  presents 


u-iiA   Frontal  B. 


—Ojjpoiit*  bone. 


(Outer  surface.) 


Fig.  15. 
Nasal  bones. 


with 

Tro  ntaZ  Szn7te. 

orest 

<wifh 
'RrpendicuZar 

jPlaU  rfEthmoid, 


groove  for  natal  nervo 

(Inner  surface.) 


A  groove  or  canal  lor  a  branch  of  the  nasal  nerve. 

The  inferior  border,  the  most  important,  has  attached  to  it 
the  lateral  cartilage  of  the  nose,  and  presents 

A  spine,  forming,  with  its  fellow,  the  nasal  angle,  a  notch 
for  exit  of  the  branch  of  the  nasal  nerve  which  grooves  the  pos- 
terior surface. 

It   articulates  with   four  hones — frontal,  ethmoid,  superior 

maxilla,  and   it-   fellow. 

It  has  no  muscular  attachments.  It  is  developed  from  one 
center. 

Tin;  malar  bones  (08  zygomaticum)  are  two  quadrilateral 
bonee  forming  the  prominence  of  the  cheek.  They  enter  into 
the  formation  of  the  orbit  and  the  zygomatic  and  temporal  fossa'. 

Each  hone  ha.-  four  processes — zygomatic,  maxillary,  fron- 
tal and  orbital. 


28 


HUMAN    ANATOMY. 


The  external  or  malar  surface  (fades  malaris)  has  attached 
to  it  the  zygomatic  muscles  (major  and  minor),  and  presents 

A  foramen  (foramen  zygomaticofaciale)  to  its  outer  side 
for  the  malar  branch  of  the  temporomalar  nerve  and  a  fora- 
men to  its  inner  side  for  the  temporal  branch  of  the  temporo- 
malar. 

The  internal  or  temporal  surface  (fades  temporalis)  artic- 
ulates with  the  superior  maxilla,  has  attached  to  it  the  masseter 
and  temporal  muscles,  and  presents  the  internal  openings  of  the 
foramen  given  above. 

The  zygomatic  process  (processus  temporalis)  forms,  with 
the  zygomatic  process  of  the  temporal  bone,  the  zygoma. 


£r£^*-E£ 


(Outer  surface.) 


Pig.  16. 
Malar  bones. 


(Inner  surface.) 


The  maxillary  process  is  triangular  and  roughened  for  ar- 
ticulation with  the  superior  maxilla. 

The  frontal  process  (processus  frontosphenoidalis)  is  artic- 
ulated with  the  external  angular  process  of  the  temporal  bone. 

The  orbital  process,  the  most  important,  articulates  by  its 
upper  and  inner  surface,  or  supero-internal  surface  (fades  or- 
oitalis)  with  the  greater  wing  of  the  sphenoid,  forming  part  of 
the  outer  wall  of  the  orbit;  the  under  surface  forms  part  of  the 
temporal  fossa,  while  the  posterior  margin  forms  part  of  the 
sphenomaxillary  fissure.  The  superior  surface  presents  two 
temporomalar  foramina  (foramen  zygomatico-orbitale) ,  trans- 
mitting temporomalar  branches  of  the  superior  maxillary  nerve. 

It  articulates  with  four  bones. — the  frontal,  sphenoid,  tem- 
poral and  superior  maxilla. 

Its  muscular  attachments  are  five — the  masseter,  temporal, 
zygomaticus  major  and  minor,  and  the  levator  labii  superioris. 

It  is  developed  from  one  ossific  center. 


OSTEOLOGY. 


20 


The  superior  maxilla  is  the  largest  bone  of  the  face, 
excepting  the  lower  jaw,  and  one  of  the  most  important,  assist- 
ing in  the  formation  of  three  cavities,  the  mouth,  nose  and 
orbit;  two  fissures,  the  sphenomaxillary  and  pterygomaxillary ; 
and  two  fossa?,  the  sphenomaxillary  and  zygomatic.  It  consists 
of  a  body  and  four  processes — the  nasal,  the  malar,  the  palatine 
and  the  alveolar  (Fig.  17). 

The  body  (corpus  maxilla)  is  excavated  to  form  the  maxil- 
lary sinus  or  antrum  Highmorianam  (sinus  maxillaris) ,  a  large, 


Incithe  fotta 


Posterior Dtnial  CanaL 


Ma.silla.ru  Tultrositu. 


"""»•  Jiicutiad*. 

Fig.  17. 
Superior  'maxillary  bone. 


irregular  triangular  cavity,  with  its  base  directed  inward,   its 
apex  upward  and  outward,  projecting  into  the  malar  process. 

It-  posterior  wall  (fades  infratemporal^:)  presents  the  'pos- 
terior dental  canals,  transmitting  the  posterior  dental  vessels 
and  nerves. 

.The  external  or  facial  surface  (fades  anterior)    (Fig.  17) 
of  the  body  presents  the  following  points: — 

Incisive  fossa,  or  myrtiform  fossa,  for  the  origin  of  the 
depressor  alae  nasi : 

Canine  fossa  (fossa,  canina) ,  for  origin  of  Levator  anguli 
oris;  •  ■••* 

Canine  eminence,  over  the  position  of  the  canine  tooth; 


30 


HUMAN    ANATOMY. 


Infraorbital  foramen  (foramen  infraorbitals),  for  the  exit 
of  the  infraorbital  nerve  and  artery. 

The  internal  surface  (fades  nasalis)  of  the  body  presents : — 

Palate  process  (processus  palatinus)  separating  the  mouth 
from  the  nasal  fossa?; 

An  irregular  opening,  the  maxillary  hiatus  (hiatus  maxil- 
laris),  leading  to  the  antrum  Highmorianum,  before  alluded  to; 

Groove  completing  the  posterior  palatine  canals  behind; 


Hones  partu&y  closing  'Orrftee  efAmtra-m 


Inferior  Twrliitatsd 
■Potato 


Ant.  Natal  Spt. 


Bristle 
pasted  rJiToutjU 
Ant.  pa-lat.  Canal 


FIG.  18. 
Superior  maxillary,  inner  surface. 


Deep  groove  An  front,  forming,  with  the  inferior  turbinated 
bone  and  lachrymal,  the  lachrymal  canal  (canalis  nasolacri- 
malis)  for  lachrymonasal  duct; 

Inferior  turbinated  crest  (crista  conclialis)  for  the  turbi- 
nated bone. 

The  superior  orbital  surface  (fades  orbitalis)  presents: — 

Infraorbital  groove  (sulcus  infraorbitaUs)  about  the  mid- 
dle for  the  infraorbital  artery  and  nerve; 

Anterior  dental  canal,  one  of  the  divisions  of  the  infra- 
orbital canal,  transmitting  the  anterior  dental  vessels  and  nerve. 

The  posterior  or  zygomatic  surface  (fades  infratemporalis) 
presents : — 

Posterior  dental  canals  (foramina  alveolaria),  transmitting 
posterior  dental  nerves  and  vessels; 


OSTEOLOGY. 


31 


Maxillary  tuberosity    {tuber  maxUlare),  articulating  with 

the  tuberosity  of  the  palate  bone; 

Groo ve,  converted  into  posterior  palatine  canal  by  the  palate 
bone  for  posterior  palatine  vessels  and  nerves. 

The  nasal  process  (processus  frontalis)  projects  upward  to 
articulate  with  the  frontal  bone,  its  external  surface  smooth, 
affording  attachment  to  several  muscles,  its  internal  surface 
forming  part  of  the  outer  wall  of  the  nose.  It  presents  the 
following : — 

Superior  turbinated  crest  (crista  ethmoidalis) ,  for  the 
middle  turbinated  bone  of  the  ethmoid; 

Inferior  turbinated  crest  (crista  conchalis)  below,  for  the 
inferior  turbinated  bone; 

Groove  at  the  posterior  margin,  forming  part  of  the  lachry- 
mal canal; 

LacJin/ma/  tubercle,  at  the  junction  of  the  nasal  process 
with  the  orbital  surface. 

The  malar  process  (processus  zygomaticus)  projects  up- 
ward and  outward  to  articulate  with  the  malar  bone. 

The  palatine  process  (processus  palatinus)  projects  from 
the  internal  surface  of  the  bone  to  form  part  of  the  roof  of  the 
mouth  and  the  floor  of  the  nose.    It  presents: — 

Anterior  palatine  canal  or  fossa  (foramen  incisivum), 
divided  into  four  canals ; 

Foramina  of  Stenson,  one  on  either  side,  transmit  the  an- 
terior branch  of  the  descending  palatine  artery; 

Foramina  of  Scarpa,  one  in  front  and  behind,  transmit  the 
nasopalatine  nerves; 

Suture  in  the  anterior  pari  showing  original  separation  of 
the  incisive  or  intermaxillary  bone  (os  incisivum)  ; 

Posterior  palatine  groove  for  the  posterior  palatine  vessels, 
and  anterior  palatine  nerves  from  Meckel's  ganglion; 

Nasal  crest  (crista  nasali*)   for  the  vomer,  and 

Anterior  nasal  spine  (spina  nasalis  anterior),  projecting 
from  the  anterior  extremity  of  the  crest. 

The  alveolar  process  (processus  alveolaris)  forms  the 
curved,  spongy  portion  for  the  insertion  of  the  upper  teeth. 
It  presents 

The  alveoli  or  Bockets  {alveoli  d-entales)  of  varying  depths, 
eight  in  the  adult,  live  in  the  child. 

"  articulates  with  nine  (9)  bones— the  ethmoid,  frontal, 
lachrymal,  nasal,  malar,  inferior  turbinated,  palate,  vomer,  and 

its  fellow  of  the  opposite  side. 


32 


HUMAN    ANATOMY. 


Its  muscular  attachments  are  nine — the  levator  labii  supe- 
rioris  alaeque  nasi,  levator  labii  superioris  proprius,  levator 
anguli  oris,  compressor  naris,  depressor  alae  nasi,  orbicularis 
palpebrarum,  inferior  obliquus,  masseter  and.  buccinator. 

It  is  developed  from  four  centers :  one  for  incisive  bone,  or 
premaxilla ;  one  for  palate  process,  or  prepalatine ;  one  for 
the  maxillary  portion,  including  the  orbital  and  facial  portion; 
and  one  for  the  malar  portion. 

Each  palate,'  bone  (os  palatinum)  is  a  thin,  -shaped 
bone,  consisting  of  an  inferior  or  horizontal  plate  and  a 
superior  or  vertical  plate. 


fl*J^S 


0*  ..-I  $""L 


S/iJi£/w£t?>aZ  JiroeesM. 


"""fty 


Fig.  19. 
Palate  bone  (viewed  posteriorly). 


HORIZONTAL    f  IAT! 

Fig.  20. 
Palate  bone  (inner  surface). 


Each  bone  assists  in  forming  three  cavities — the  outer  wall 
and  floor  of  the  nose,  the  roof  of  the  mouth  and  floor  of  the 
orbit;  two  fossae — the  pterygoid  (fossa  pterygoid ea)  and  spheno- 
maxillary (fossa  pterygopalatina) ,  and  one  fissure — the  spheno- 
maxillary (fissura  oroitalis  inferior). 

The  horizontal  plate  (pars  liorizontalis)  is  quadrilateral. 
Its  inferior  surface  (fades  palatina)  presents 

A  ridge  for  the  aponeurosis  of  the  tensor  palati  muscle ; 

A  groove  (sulcus  pterygopalatinus)  entering  into  the  for- 
mation of  the  posterior  palatine  canal; 

Accessory  palatine  foramina  (canal es  palatini)  for  poste- 
rior descending  palatine  nerves. 

Its  posterior  border  (spina  nasalis  posterior)  presents 

The  posterior  nasal  spine  (crista  nasalis)  for  the  azygos 
uvulae  muscles. 


OSTEOLOGY.  33 

The  infernal  border  articulates  with  its  fellow  and  presents 

A  crest  for  the  vomer. 

The  vertical  or  perpendicular  plate  (.pars  perpendicularis) 
projects  upward  and  inward,  terminating  above  in  two  well- 
marked  processes — the  orbital  and  sphenoidal  processes. 

The  internal  or  nasal  surface  (fades  nasalis)  forms  part 
of  the  outer  wall  of  the  nasal   fossa,  and  presents 

An  inferior  turbinated  crest  (crista  conchalis)  for  the  in- 
ferior turbinated  bone; 

A  superior  turhinated  crest  (crista  ethmoidalis)  for  the 
middle  turbinated  bone,  separating  the  middle  from  the  in- 
ferior meatus  of  the  nose. 

The  external  or  maxillary  surface  (fades  maxillaris)  forms 
part  of  the  sphenomaxillary  i'ossa  and  covers  part  of  the  orifice 
of  the  antrum. 

It  presents  at  the  posterior  part 
•     A  groove,  converted   by  the  superior  maxilla,  into  a  canal, 
the  posterior  palatine,  for  the  passage  of  the  descending  palatine 
vessels  and  the  descending  palatine  branches  from  Meckel's  gan- 
glion. 

The  anterior  border  presents 

The  maxillary  process  (processus  maxillaris),  closing  part 
of  the  orifice  of  the  antrum. 

The  pterygoid  process  (processus  pyramidalis),  or  tuberos- 
ity of  the  palate,  at  its  lower  part  wedged  in  between  the  ptery- 
goid plates  of  the  sphenoid,  and  giving  origin  to  part  of  the 
superior  constrictor  and  the  internal  pterygoid  muscle. 

Foramina  of  accessory  descending  palatine  canals,  for  pos- 
terior descending  branches  from  Meckel's  ganglion. 

The  obbital  process  (processus  orbitalis),  a  large,  hollow, 
triangular  process,  is  so  called  from  its  forming  part  of  the 
orbit. 

It  presents 

The  anterior  or  maxillary  articular  surface  for  superior 
maxilla  ; 

The-  posterior  or  sphenoidal  articular  surface  for  sphenoid; 

The  internal  or  ethmoidal  articular  surface,  for  ethmoid; 

A  superior  or  orbital  surface,  a  smooth  portion  entering  into 
the  format  ion  of  the  orbit  ; 

An  external  or  zygomatic  surf  ace],  also  smooth,  forming  part 
of  the  zygomatic  fossa. 

Tin.  sphenoidal   pbocess    (processus  sphenoidalis)    is  a 

-mall,  thin    plate  of  hone   which   articulates  by   its   upper  surface 
with    the    -phenoidal    turbinated    hone;    its    inner    surface    forms 

:', 


34 


HUMAN    ANATOMY. 


part  of  the  nasal  fossa,  and  its  outer  surface  articulates  with  the 
pterygoid  process  of  the  sphenoid  and  forms  part  of  the  spheno- 
maxillary fossa. 

The  anterior  border  forms  a  part  of  the  sphenopalatine  fora- 
men, which  passes  between  the  orbital  process  and  the  sphenoidal 
process. 

It  articulates  with  six  (6)  bones. — ethmoid,  sphenoid,  supe- 
rior maxillary,  vomer,  inferior  turbinated,  and  fellow  of  the 
opposite  side. 

Its  muscular  attachments  are  azygos  uvula?,  tensor  palati, 
internal  and  external  pterygoid  and  superior  constrictor.  It 
has  one  ossific  center  at  the  junction  of  the  plates. 

The  inferior  turbinated  bones  (concha  nasalis  inferior) 
are  small,  scroll-like  bones,  situated  on  the  outer  wall  of  the 


(Inner   surface.) 


Fig.  21. 
Inferior   turbinated   bones. 


(Outer  surface.) 


nasal  fossa,  separating  the  middle  from  the  inferior  meatus. 
Each  presents  two  surfaces  and  three  processes — the  lachrymal, 
ethmoidal  and  maxillary. 

The  internal  surface  is  lined  in  the  recent  state  with  the 
mucous  membrane  of  the  nose. 

The  external  surface  is  attached  to  the  superior  maxilla  and 
palate  bone,  and  presents  above  the  three  processes. 

The  lachrymal  process  (processus  lacrimalis)  forms  part 
of  the  lachrymal  canal,  articulating  with  the  superior  maxilla 
and  the  lachrymal  bone. 

The  ethmoidal  process  (processus  ethmoidal  is)  articulates 
with  the  hook-like  process  of  the  ethmoid  bone. 

The  maxillary  process  (processus  maxillaris)  projects  out- 
ward and  downward  from  the  ethmoidal  process,  and  narrows 
the  orifice  of  the  antrum. 

It  articulates  with  four  bones — ethmoid,  palate,  superior 
maxillary  and  lachrymal. 

Muscular  attachments,  none.     It  has  one  ossific  center. 


OSTEOLOGY. 


35 


The  vomer  is  a  thin,  triangular  plate  of  bone,  contributing 
to  form  part  of  the  septum  nasi.     It  is  usually  bent  to  one  side, 

The  superior  border  presents  a  groove  with  overlapping 
lamina?,  or  vaginal  processes  (alw  vomeris)  for  articulation  with 
the  rostrum  and  vaginal  processes  of  the  sphenoi  I. 

The  inferior  border  articulates  with  the  crests  of  the  supe- 
rior maxilla?  and  palate-bones. 

The  posterior  border  is  smooth  and  free,  forming  the  pos- 
terior nasal  septum. 

The  hi  I  end  surfaces  present 

Furrows  foT  blood-vessels,  and 

Nasopalatine  grooves  for  the  nasopalatine  nerves,  which 
descend  to  the  foramina  of  Scarpa. 


az* 


It  articulates  with  six  hones — the  ethmoid,  sphenoid,  two 
palate  and  two  superior  maxilla?. 

It  has  no  muscular  attachments.  It  is  developed  from  a 
single  ossific  center,  although  it  begins  as  two  cartilaginous 
laminae,  which  coalesce. 

The  infebiob  maxilla,  or  mandible  (mandibula),  is  the 
largesl  bone  in  the  face,     it  consists  of  a  body  and  two  rami. 

The  body  (corpus  mandibular)  is  the  horizontal,  horseshoe- 
like  portion,  containing  the  lower  teeth. 

The  external  surface  presents  from  before  backward: — 

Symphysis,  a  vertical  median  line  indicating  the  junction 
of  the  vaginal  halves ; 

.Mental  process  ( prot  uberan  I  in  mentalis),  a  triangular 
prominence  cons!  ituting  the  chin  ; 

Incisive  fossa,  for  the  origin  of  the  Levator  labii  inferioris; 

Mental   foramen    (foramen   mentale),   for  the  exit   of  the 

menial  nerve  and  artery  ; 


36 


HUMAN    ANATOMY. 


External  oblique  line  (linea  obliqua),  running  backward 
and  upward  from  the  mental  process,  for  the  attachment  of  the 
depressor  anguli  oris  and  depressor  labii  inferioris. 

The  internal  surface  presents,  from  before  backward : — 

Genial  tubercles  (spina?  mentales),  four  in  number,  for  at- 
tachment of  the  geniohyoglossi  muscles  above  and  the  genio- 
hyoidei  below; 

Sublingual  fossa  (fovea  sublingualis),  for  the  sublingual 
gland ; 

Internal  oblique  line  or  mylohyoid  ridge  (linea  mylo- 
hyoidea),  for  the  attachment  of  the  superior  constrictor,  the 
mylohyoid  muscles,  and  the  pterygomaxillary  ligament; 


i^v-4 


Fig.  23. 
Inferior  maxillary   bone. 

Submaxillary  fossa  (fovea  submaxillar  is) ,  for  the  submax- 
illary gland. 

The  superior  or  alveolar  border  (pars  alveolaris)  presents 
sixteen  cavities  (ten  in  childhood)  for  the  teeth. 

The  inferior  border,  or  basilar  portion  (basis  mandibular) 
is  grooved  posteriorly  for  the  facial  artery. 

The  ramus,  or  perpendicular  portion  (rami  mandibular), 
on  either  side  is  somewhat  quadrilateral,  and  presents  the  fol- 
lowing points : — 

The  internal  surface  of  ramus; 

Foramen  (foramen  mandibulare)  of  inferior  dental  canal 
(canalis  mandibular),  for  inferior  dental  vessels  and  nerve; 

Mylohyoidean  groove  (sulcus  mylohyoideus) ,  described 
above ; 


OSTEOLOGY. 


37 


Spine,  for  attachment  of  the  internal  lateral  ligament  of 
the  lower  jaw. 

The  upper  border  is  surmounted  by  two  processes,  the  coro- 
noid  and  the  condyloid  processes,  separated  by  the  sigmoid  notch. 

The  coronoid  process  (processus  coronoideus)  is  in  front, 
and  affords  attachment  for  the  temporal  muscle. 

The  condyloid  process  (processus  condyloid  eus)  articulates 
with  the  glenoid  fossa  of  the  temporal  bone,  being  supported 
upon  a  constricted  portion,  the  neck  (collum-  mandibular) ,  which 
receives  the  insertion  of  the  external  pterygoid  muscle,  and 


MIO'UVO-CLOSSUS 
CtNIO-HVOIDIU* 


jfyjcly'J  R'fy 


B  a  dy 

Fig.  24. 

Left  half  of  inferior  maxillary   bone,   inner  surface. 

presents  to  its  outer  side  a  tubercle  for  the  external  lateral 
ligament  of  the  lower  jaw. 

The  sigmoid  notch  (incisura  mandibula>)  is  crossed  by  the 
masseteric  vessels  and  nerve. 

The  lower  border  presents : — 

Angle  of  the  jaw  (angulus  mandibulce) ,  the  point  of  junc- 
tion of  the  ramus  with  the  body ; 

Rough  surface,,  for  attachment  of  the  stylomaxillary  liga- 
ment, and  on  its  inner  side  the  internal  pterygoid  muscle,  and 
on  its  outer  side  the  masseter. 

It  articulates  with  the  two  temporal  bones. 

The  muscular  attachments  are  fifteen  pairs;  to  the  external 
surface,  sis — depressor  anguli  oris,  depressor  labii  inferioris, 
levator  labii  inferioris,  orbicularis  oris,  platysma  myoides  and 
buccinator;   from   the   interna]   Burface  of  the   body,  five — the 


38  HUMAN    ANATOMY. 

geniohyoglossus,  geniohyoid,  mylohyoid,  digastric  and'  superior 
constrictor;  and  to  the  ramus,  four — the  masseter,  internal  and 
external  pterygoids  and  temporal. 

It  has  two  ossific  centers,  one  for  each  lateral  half,  devel- 
oped partly  from  membrane,  partly  from  cartilage,  being  pre- 
ceded in  time  only  by  one  bone — the  clavicle. 

Changes  in  Lower  Jaw. — Certain  changes  occur  in  the  size 
and  shape  of  the  lower  jaw  as  age  advances. 

At  birth  the  body  is  shell-like,  containing  sockets  for  the 
ten  temporary  teeth,  the  mental  foramen  is  large  and  opens 
beneath  first  molar,  and  the  coronoid  process  is  large  and  at 
right  angles  to  base. 


Thyrohyoid* 
Slijlo-hyoid. 
^Omo-hyoid, 
Mylo-hyoidi 
Sterno-hyoid: 

Fig.  25. 
The  hyoid  bone. 

In  adults  the  base  and  alveolar  process  are  equal  in  size, 
the  mental  foramen  opens  midway  between  upper  and  lower 
borders,  and  the  rami  are  at  nearly  right  angles  to  base. 

In  advanced  age  the  loss  of  the  teeth  and  alveolar  borders 
greatly  reduces  the  body,  the  mental  foramen  opens  near  the 
alveolar  border,  and  the  rami  are  united  at  very  obtuse  angles 
with  the  base. 

The  hyoid  bone,  or  lingual  bone  (os  liyoicleum)  is  a  small, 
U-shaped  bone' situated  at  the  base  of  the  tongue,  consisting  of 
a  body  ( corpus  ossei  hyoidei) ;  two  greater  and  two  lesser  cornua. 

It  is  supported  by  the  stylohyoid  ligament  from  the  styloid 
processes  of  the  temporal  bones. 

The  anterior  surface  is  divided  by  a  crucial  ridge  into  four 
depressions  for  muscular  attachments,  and  its  center  presents  a 
tubercle. 

The  posterior  surf  ace  is  in  relation  with  the  epiglottis,  being 
separated  by  the  thyrohyoid  membrane. 


OSTEOLOGY.  39 

The  upper  and  hirer  borders  afford  attachment  to  muscles, 
and  the  lateral  surfaces  are  mounted  with  cartilage  for  articula- 
tion with  the  greater  comua. 

The  greater  comua,  or  thyrohyals  (comua  majora),  pro- 
ject backward,  afford  attachment  to  the  hyoglossus,  thyrohyoid, 
and  middle  constrictor  of  the  pharynx,  and  terminate  behind 
m  a  tubercle  for  the  attachment  of  the  thyrohyoid  ligament. 

The  lesser  comua,  or  ceratohyals  (comua  minora),  are  two 
tuber-like  projections  attached  at  the  junction  of  the  body  with 
the  greater  comua,  and  receiving  the  insertion  of  the  stylohyoid 
ligaments.     They  do  not  articulate  with  any  bone. 

Its  muscular  attachments  are  ten — the  Hngualis,  hyoglossus, 
geniohyoglossus,  middle  constrictor,  stylo-,  mylo-,  genio-,  sterno- 
thyro-,  omo-  hvoid;  also  aponeurosis  of  digastric  and  stylo- 
hyoid ligament. 

Os,sific  centers,  five — one  for  body  and  one  for  each  horn. 

The  Sutures  and  Fontanelles. — The  sutures  are  divided 
into  three  sets,  those  of  the  vertex,  side,  and  base  of  the  skull. 

At  the  vertex  of  the  skull  there  are  three : — 

Sagittal,  or  interparietal    (sutura  sagittalis)  ; 
Coronal,   or    frontoparietal    (sutura  coronalis)  ; 
Lambdoid,  or  occipitoparietal    (sutura  lambdoid ea) . 

At  the  side  of  the  skull  are  three : — 

Sphenoparietal    (sutwa  sphenoparietalis)  ; 

Squamoparietal,  or  squamous    {sutura  squamosa); 
Mastoparietal   (sutura  parietomastoidea) . 

At  the  base  of  the  skull  are  nine:— 

Basilar,  in  center    (fissura  spheno-occipitalis) , 
Petro-occipital    ( fissura  petro-occipitalis) ,  ~\ 

Maato-oecipital    |  sutura  occipitomastoidea) ,       Lon  either  side. 
Petrosphenoidal    (fissura  sphenopetrosa) , 
Squamosphenoidal    (sutura  sphenosquamosa) ,  J 

The  sutures  of  the  face  are  very  numerous,  but  the  most 
important  are : — 

Zygomatic,  at  tin-  temporomalar  junction; 

Transverse,  posses  from  one  external  angular  process  to  the  other, 
and  connects  the  frontal  with  the  malar,  ethmoid,  sphenoid,  lachrymal, 
superior  maxillary  and  nasal  bones; 

intermaxillary,  the  median  suture  between  the  superior  maxillae; 

Symphysis,  Hie  remains  of  a  fetal  suture. 

The  fontanelles  (fontieuli)  are  six  membri us  intervals  in 

the  infant's  skull  corresponding  to  the  four  angles  of  the  parietal 
bones.    The  anterior  or  bregmatic  (fontwulus  frontalis),  larger 


40  HUMAN    ANATOMY. 

and  lozenge-shaped,  is  at  the  junction  of  sagittal  and  coronal 
sutures;  the  posterior  (fonticulis  occipitalis) ,  smaller  and  tri- 
angular, is  at  the  junction  of  sagittal  and  lambdoid  sutures;  and 
the  four  lateral  are  at  anterior  and  posterior  inferior  angles  of 
parietal  bones  (fonticulus  sphenoidalis  et  fonticulus  mastoideus) . 

The  Wormian,  supernumerary,  sutural  or  epactal  bones 
(ossa  triquetra)  are  irregular  bones  interposed  in  intervals  be- 
tween the  cranial  bones,  chiefly  in  the  course  of  the  lambdoid 
suture. 

Congenital  fissures  from  an  arrest  of  ossification  also  occur, 
the  most  common  being  the  parietal  and  sagittal  fissures 
(Treves). 

FOSSAE  OF  SKULL. 

The  fossa?  at  the  lateral  region  of  the  skull  are  temporal, 
zygomatic,  or  infratemporal,  and  sphenomaxillary  or  pterygo- 
palatine fossa. 

The  temporal  fossa  (fossa  temporalis)  is  deeply  concave  in 
front,  convex  behind ;  it  is  formed  by  parts  of  five  bones — frontal, 
malar,  sphenoid,  temporal  and  parietal.  It  is  bounded  above 
and  behind  by  temporal  ridge;  in  front  by  the  sphenoid,  malar 
and  frontal;  below  and  externally  by  zygoma,  and  pterygoid 
ridge  on  greater  wing  of  sphenoid.  It  is  crossed  by  six  sutures — 
sphenomalar,  sphenoparietal,  squamoparietal,  squamosphenoidal, 
coronal  and  transverse  facial.  It  opens  below  into  the  zygo- 
matic fossa,  is  filled  by  the  temporal  muscle,  and  lodges  the  deep 
temporal  vessels. 

The  zygomatic  or  infratemporal  fossa  (fossa  infratem- 
poralis)  is  an  irregular  cavity  containing  parts  of  temporal,  ex- 
ternal and  internal  pterygoid  muscles,  and  is  bounded  above 
by  pterygoid  ridge  of  sphenoid  and  squamous  portion  of  tem- 
poral, below  by  alveolar  border  of  superior  maxilla,  in  front 
by  tuberosity  of  superior  maxillary,  behind  by  border  of  ptery- 
goid process,  externally  by  zygoma  and  ramus  of  lower  jaw  and 
internally  by  external  pterygoid  plate.  It  is  traversed  by  two 
fissures — sphenomaxillary  and  pterygomaxillary. 

The  sphenomaxillary  fissure  (fissura  orbitalis  inferior) 
connects  the  zygomatic,  temporal  and  sphenomaxillary  fossa?, 
and  transmits  the  infraorbital  artery,  ascending  branches  of 
Meckel's  ganglion,  the  superior  maxillary  nerve  and  its  orbital 
branch. 

It  is  bounded  above  by  great  wing  of  sphenoid,  below  by 
superior  maxilla  and  part  of  palate  bone;  internally  it  opens  into 
pterygomaxillary  fissure  and  externally  part  of  malar  bone. 


OSTEOLOGY. 


41 


The  pterygomaxillary  fissure  connects  the  zygomatic  and 
sphenomaxillary  fossa1,  passing  vertically  between  pterygoid 
process  of  sphenoid  and  superior  maxillary  bone,  and  transmits 
branches  of  internal  maxillary  artery. 

The  sphenomaxillary  or  pterygopalatine  fossa  (fossa  ptery- 
gopalatina)    is  a  triangular  cavity,  bounded  above  by  body  of 


Fig.  26. 

1.  median  suture;  2,  anterior  palatine  foramen;  3,  posterior  pala- 
tine foranif-n:  4,  posterior  nasal  spine;  ;j,  vomer;  6,  hamular  process; 
7,  pterygopalatine  canal;  8,  external  plate;  9,  scaphoid  fossa;  10, 
foramen  ovale;  11,  foramen  spinosum;  12,  foramen  lacerum  medium; 
13,  zygoma;  14,  basilar  suture;  15,  gienoid  fossa;  16,  external  audi- 
tory meatus;  17,  mastoid  process;  18,  styloid  process;  1!»,  carotid 
foramen;  20,  foramen  lacerum  posterius;  21,  occipital  condyles;  2'1. 
i-  process;  23,  foramen  magnum;  24,  occipital  crest;  25,  Inferior 
curved  lines. 


sphenoid  and  orbital  plate  of  palate-bone,  within  by  vertical 
plate  of  palate,  in  front  by  superior  maxillary,  and  behind  by 
pterygoid  process  of  Bphenoid.     Jt  lias  communicating  with  it 


42 


HUMAN    ANATOMY. 


Three  f  ossse — orbital,  nasal  and  zygomatic ; 
Three  fissures — sphenoidal,   sphenomaxillary   and  pterygo- 
maxillary ; 

Two  cavities — cranial  and  buccal;  and 


TENDS   OCULI 


Ant.  Wdsal  Spine 
IneLrive  fossa,. 


Grew* far  Taci'ai  Cft 


Fig.  27. 
Facial  portion  of  skull. 

.  Five  foramina — foramen  rotundum,  Vidian  and  pterygo- 
palatine posteriorly;  sphenopalatine,  on  inner  wall,  and  pos- 
terior palatine  canal,  and  (sometimes)  accessory  posterior  pala- 
tine canals  below.  It  contains  internal  maxillary  artery,  superior 
maxillary  nerve  and  Meckel's  ganglion. 

The  orbits  are  two  pyramidal  cavities,  situated  between 
the  nose  and  external  angular  processes,  the  forehead  and  face, 
their  bases  outward  and  forward,  their  apices  converging  toward 


OSTEOLOGY.  43 

the  body  of  the  sphenoid  bone.  They  contain  the  eye  and  its 
appendages,  and  are  each  formed  by  seven  bones — frontal,  eth- 
moid, sphenoid  (entering  into  both  cavities),  superior  maxil- 
lary, lachrymal,  malar  and  palate  (separate  in  each).  The 
loof  (paries  superior),  concave,  presents: — 

Externally,  depression  for  lachrymal  gland ; 

Internally,  depression  for  pulley  of  superior  oblique; 

Posteriorly,  a  suture  between  lesser  wing  and  frontal  bone. 

It  is  formed  by  the  orbital  plate  of  frontal  and  lesser  wing 
of  sphenoid. 

The  floor  (paries  inferior)  is  short  and  flat,  and  presents: — 

Internally,  a  depression  for  inferior  oblique  muscle; 

Middle,  the  infraorbital  groove  for  nerve  and  artery; 

Externally,  suture  of  superior  maxillary  and  malar ; 

Posteriorly,  suture  between  palate  and  superior  maxillary. 

It  is  formed  by  orbital  processes  of  malar  and  superior 
maxilla  and  orbital  surface  of  palate. 

Inner  wall  (paries  mediaiis)  presents  crest  of  lachrymal 
bone,  lachrymal  groove,  sutures  between  ethmoid  and  sphenoid 
and  ethmoid  and  lachr}'mal. 

It  is  formed  by  Lachrymal,  parts  of  ethmoid,  and  sphenoid 
and  nasal  process  of  superior  maxilla. 

The  outer  wall  (paries  lateralis)  presents  suture  between 
malar  and  sphenoid  and  orifices  of  malar  canals.  It  is  formed 
by  orbital  plate  of  sphenoid  and  orbital  process  of  malar. 

The  angles  of  the  orbit  are  four — superior  internal  anil 
external,  inferior  internal  and  external. 

They  present  the  following:- — 

Superior  internal  angle: 

Foramen  ethmoidal  anterior,  transmitting  anterior  eth- 
moidal vessels  and  nasal  nerve; 

Foramen  ethmoidal  posterior,  transmitting  posterior  eth- 
moidal artery  ami  vein; 

Suture  between  frontal  and  ethmoid,  and  frontal  and  lach- 
rymal ; 

Superior  external  angle: 

Sphenoidal  fissure,  or  foramen  lacerum  anterius,  transmit- 
ting third,  fourth,  ophthalmic  division  of  fifth  and  sixth  nerves; 
orbital  branch  of  middle  meningeal  artery,  filaments  of  cavern- 
ous plexus  of  sympathetic,  recurrenl  branch  id'  lachrymal  artery, 
and  ophthalmic    vein    and    process   of   dura    mater. 

Su/urr  between  greal  wing  of  sphenoid  and  malar  bone, 
Inferior  internal  angle: 


44  HUMAN    ANATOMY. 

Suture  between  superior  maxillary  and  palate  bones, 
uniting  with  lachrymal  and  os  planum  of  ethmoid; 

Inferior  external  angle: 

Sphenomaxillary  fissure,  for  passage  of  superior  maxillary 
nerve  and  its  orbital  branch,  infraorbital  vessels,  and  ascending 
branches  from  Meckel's  ganglion. 

The  circumference  is  bounded : — 

Inner  side  by  nasal  process  of  superior  maxilla  and  internal 
angular  process  of  frontal; 

Outer  side  by  external  angular  process  of  frontal  and  malar 
bone; 

Above  {mar go  supraorbitalis)  by  supraorbital  arch; 

Below  {margo  infraorbitalis)  by  lachrymal,  superior  max- 
illa and  malar. 

It  presents  sutures  malomaxillary  below; 

Sutures  frontomalar .  to  outer  side ; 

Sutures  frontomaxillary  to  inner  side; 

Supraorbital  notch  or  foramen  above,  for  passage  of  supra- 
orbital nerve,  artery  and  vein,  and  forms  part  of  lachrymal 
groove. 

The  apex  presents : —    • 

Optic  foramen,  for  passage  of  optic  nerve  and  ophthalmic 
artery. 

Each  orbit  presents  nine  (9)  openings,  as  follows: — - 

1.  Supraorbital  foramen  for  passage  of  supraorbital  artery, 
vein  and  nerve; 

2.  Infraorbital  canal  for  infraorbital  nerve  and  artery; 
'3.  Anterior  ethmoidal  foramen  for  anterior  ethmoidal  ar- 
tery, vein,  and  the  nasal  nerve; 

4.  Posterior  ethmoidal  foramen  for  posterior  ethmoidal  ar- 
tery and  vein; 

5.  M'alar  foramina,  for  malar  and  temporal  branches  of 
temporomalar  nerve ; 

6.  Lachrymal  canal,  for  lachrymonasal  duct; 

7.  Sphenomaxillary  fissure,  for  infraorbital  vessels,  supe- 
rior maxillary  nerve  and  its  orbital  branches,  and  ascending 
branches  from  sphenopalatine  (Meckel's)  ganglion; 

8.  Foramen  lacerum  anterius  (or  sphenoidal  fissure),  for 
third,  fourth,  ophthalmic  division  of  fifth  and  sixth  nerves,  oph- 
thalmic vein,  branches  of  lachrymal  and  meningeal  arteries,  fila- 
ments of  the  sympathetic  nerve  and  a  process  of  dura  mater  for 
ensheathing  of  the  nerve ; 

9.  Optic  foramen,  for  optic  nerve  and  ophthalmic  artery. 


OSTEOLOGY. 


45 


The  nasal  fossae  (cavum  nasi)  consist  of  two  large  cavi- 
ties separated  from  each  other  by  the  septum  nasi  (septum  nasi 
osseum),  and  opening  in  front  by  the  anterior  nares  (apertura 
piriformis),  and  behind  into  the  pharynx  by  the  posterior  nares 

(choanal). 

They  are  formed  by  fourteen  bones — the  frontal,  ethmoid, 
sphenoid  and  all  the  bones  of  the  face  except  the  lower  jaw 
and  malar. 


Aoof 

Ratal 
Jfatal  .J/iiie  of  Frontal  But* 
BcramulFUu  •f£tiwtad 
SjJmmJ 


Prolt  paticJ  Amiga 
HatO'ltwhrymal  Co-Mat 

MnmtU  pmtttJi&tmjk 
/itfunJtla/um  ■ 


Ouur  Wall 

■fawn.!,  Pre.:  trfSuptfa 
J.nrKrynuiL 

L',uif<nmIyoa  <f  ditto 
fnfcner  I'urbxiuilcS 

PalaU 
Sujxru/r  Hcatu* 
Muidll  Meat** 
Inferior  Keatut 


floor 

Anl.Xa-tal  Sp 

Palatr  troc  of  Sup  Man- 

Palate  Proc.  efTalaU- 

Post. Natal  Spin* 

int.  PalaUiit  Canal 


Fig.  28. 
Nasal   meatuses. 

They  have  each  four  sinuses  opening  into  them — the  eth- 
moidal and  antrum  of  Highmore  (maxillary)  on  either  side,  the 
sphenoidal  behind  and  the  frontal  above,  and  communicate  with 
the  mouth  by  the  anterior  palatine  canal,  with  the  orbit  by  the 
lachrymal  canal,  with  the  sphenomaxillary  fossa  by  the  spheno- 
palatine foramen,  and  with  the  cranium  by  the  olfactory  fo- 
ramina. 

They  arc  each  hounded  by  an  outer,  inner,  upper  and  lower 

wall. 

The  outer  wall  is  divided  by  the,  middle  turbinated  process 
of  the  ethmoid  and  the  inferior  turbinated  bone  into  the  superior. 

middle  and    inferior  meat  uses  of   the   uosr. 

The  superior  meatus  (meatus  nasi  superior),  the  smallest, 
has  three  orifices  opening  into  it: — 


46  'HUMAN    ANATOMY. 

The  posterior  ethmoidal  cells; 

The  sphenoidal  sinuses,  opening  behind  the  superior  tur- 
binated bone  and 

The  sphenopalatine  foramen,  for  transmission  of  spheno- 
palatine vessels  and  superior  nasal  and  nasopalatine  nerves. 

The  middle  meatus  (meatus  nasi  medius)  has  two  ori- 
fices : — 

The  infundibulum  (infundibulum  ethmoidal  e),  communi- 
cating with  the  frontal  sinuses,  and  through  them  with  the  an- 
terior ethmoidal  cells  and  the  orifice  of  the  antrum  or  maxillary 
sinus. 

The  inferior  meatus  (meatus  nasi  inferior),  the  smallest, 
has  two  orifices  : — 

The  lachrymal  canal,  for  lachrymonasal  duct  and  the  an- 
terior palatine  canals,  for  anterior  branches  of  descending  pala- 
tine arteries  (foramina  of  Stenson)  and  nasopalatine  nerves 
(foramina  of  Scarpa). 

The  inner  wall  (septum  nasi)  is  formed  by  the  vomer, 
vertical  plate  of  the  ethmoid  and  the  triangular  cartilage  of  the 
nose,  with  portions  of  the  following  bones :  nasal  spine  of  the 
frontal,  rostrum  of  the  sphenoid,  and  the  crests  of  the  nasal, 
palate  and  superior  maxillary  bones.  It  is  grooved  by  the  naso- 
palatine and  other  nerves. 

The  upper  wall  or  roof  presents  the  following  from  before 
backward : — 

The  nasal  slit  in  the  cribriform  plate,  for  passage  of  nasal 
nerve,  a  branch  of  ophthalmic ; 

The  olfactory  foramina,  for  olfactory  filaments  and 

Openings  or  orifices  posteriorly  of  the  sphenoidal  sinuses. 

The  lower  wall  or  floor  presents  from  before  backward : — 

The  anterior  nasal  spine; 

The  anterior  palatine  canals,  given  above ; 

Crest  or  ridge  for  vomer; 

Suture  between  superior  maxillary  and  palate-bone  and 

Posterior  nasal  spine. 

FORAMINA  AT  THE  BASE  OF   THE  SKULL. 

Anterior  fossa  (fossa  cranii  anterior)  presents  one  single 
foramen  and  four  in  pairs : — 

Foramen  ccecum  transmits  a  small  vein  to  the  superior 
longitudinal  sinus; 

Ethmoidal  fissure  transmits  nasal  branch  of  ophthalmic 
nerve ; 


OSTEOLOGY. 


47 


Ant  pattrftne  fotJT 

t*  It  ft  Nttto-pattxt. 

Transmit* Ant palat  vest. 
mmU*    rigJttNatopalat.r 


toxy  palatini 

Frrtxtmtta. 


!Sj>It61tQL<t.prOC.  of  P*l*t0. 

Tterygo-paUtiJi*  C. 


FMryTu/eal  Spin*  for  MP-  CONCTKlfA 


Fig.  29. 
Base  of  skull,    external  surface. 


48  HUMAN  anatomy. 

Olfactory  foramina,  for  filaments  of  olfactory  bulb; 

Anterior  ethmoidal  transmit  anterior  ethmoidal  artery  and 
nasal  nerve; 

Posterior  ethmoidal  transmits  posterior  ethmoidal  artery 
and  vein. 

Middle  fossa  (fossa  cranii  media)  presents  nine  (9) 
pairs : — 

Optic  foramen  transmits  the  optic  nerve  and  ophthalmic 
artery ; 

Foramen  lacerum  anterius,  or  sphenoidal  fissure  (fissura 
orbitalis  superior),  transmits  third,  fourth,  three  branches  of 
the  ophthalmic  division  of  the  fifth  and  the  sixth  nerve,  orbital 
branch  of  the  middle  meningeal,  recurrent  branch  from  the 
lachrymal  arter}^,  filaments  of  the  sympathetic  nerve,  and 
ophthalmic  vein; 

Foramen  rotundum  transmits  second  division  of  fifth  or 
superior  maxillary ; 

Foramen  Vesalii  transmits  a  small  vein; 

Foramen  ovale  transmits  third  division  of  fifth  or  inferior 
maxillary  nerve,  small  petrosal  nerve  and  small  meningeal 
artery ; 

Foramen  spinosum  transmits  middle  or  great  meningeal 
artery ; 

Foramen  lacerum  medium  transmits  the  internal  carotid 
artery,  carotid  plexus,  a  branch  of  ascending  pharyngeal  artery 
and  the  Vidian  or  large  petrosal  nerve; 

Foramen  for  lesser  petrosal  nerve,  and 

Hiatus  Fallopii  transmits  petrosal  branch  of  middle  menin- 
geal artery  and  petrosal  branch  of  the  Vidian  nerve. 

Posterior  fossa  (fossa  cranii  posterior)  presents  six  pairs 
and  one  single  one  :— 

Meatus  auditorius  intemus  transmits  auditory  artery,  facial 
and  auditory  nerves; 

Aquceductus  vestibuli  transmits  small  artery  and  vein  and 
lodges  a  process  of  dura  mater ; 

Foramen  lacerum  posterius,  or  jugular  foramen,  transmits 
inferior  petrosal  sinus  and  lateral  sinus,  forming  the  internal 
jugular  vein,  glossopharyngeal,  pneumogastric,  spinal  accessory 
nerves  and  meningeal  branches  of  ascending  pharyngeal  and 
occipital  arteries; 

Mastoid  foramen  transmits  small  vein  to  the  lateral  sinus 
and  small  artery  from  occipital  to  the  dura  mater; 

Anterior  condyloid  foramen  transmits  meningeal  branch 
from  ascending  pharyngeal  artery  and  hypoglossal  nerve ; 


OSTEOLOGY. 


49 


Viprtl 


Creevt  fr*  Super  l-iaituj.fftmtt 
Oromtfar  AlOsr.  M.rSnytalA 
F'mmtn  Cxtur*- 
Crista-  CniU 
m     Slit  ft 

Anterior  Xthmoidnl  £, 
Or  if  lets  for  ^factory  ne 
Fom+xtxov  Edimoldal  Ft 

Ethmoidal  Spins 


Olfactory  Cr, 

Ofti*     Foramen 

Opt  Co  Qtqov*. — .  t^ 

OL 

Aftter/or  Clirwid  proa. 

KiJJU   CUnoi'J  j? rev 

Fotterior  Cliwrid  proa 

Greov*  f**  6*  «+n>m 

Far-   Lirrrurti    medium 

Crifiot  of  Carried  Canal 

<wi    t?r  Catterum  Gavalcon 


Mtafut  Auditor.  Interim* 

Slit  for  DuT*-M*t*r 

Sup.  FttTosttl  yrvorv 

Fit.  loeerum  paattruu 

Anterior  Condyloid  Ton 

Aqurduoe.  VetttbmU 

Voct+rior  Condyloid  Fom 


Meutotd  Fox 

JjMt.  JKsnlnqsal  GrewiM. 


Ida.  30. 

Floor  of   the  cranium. 


50  HUMAN   ANATOMY. 

Posterior  condyloid  foramen  transmits  posterior  condyloid 
vein; 

Foramen  magnum  transmits  vertebral  arteries,  medulla  ob- 
longata and  its  membranes  and  the  spinal  accessory  nerves. 

OTHER  FORAMINA  OF  SKULL. 

The  external  surface  of  the  base,  or  basilar  surface,  pre- 
sents seven  pairs : — 

Palatal  portion: — 

Incisive  foramina  transmit  nerves  and  vessels  to  the  incisor 
teeth ; 

Foramina  of  Stenson  transmit  the  anterior  branch  of  the 
posterior  palatine  vessels; 

Foramina  of  Scarpa  transmit  the  right  and  left  nasopala- 
tine nerve; 

Posterior  palatine  foramina  transmit  posterior  palatine  ves- 
sels and  descending  palatine  nerve; 

Accessory  palatine  foramina  transmit  posterior  palatine 
nerves ; 

Pterygopalatine  canals  transmit  pterygopalatine  vessels, 
and  the 

Pterygoid  or  Vidian  canal  (canalis  pterygoideus)  transmits 
the  Vidian  artery  and  nerve. 

Lateral  portion  presents  nine  pairs : — 

Opening  of  the  Eustachian  tube; 

Opening  of  the  tensor  tympani  canal  transmits  the  tensor 
tympani  muscle; 

Glaserian  fissure  transmits  the  tympanic  branch  of  the  in- 
ternal maxillary  artery  and  lodges  the  processus  gracilis  of  the 
malleus ; 

Canal  of  Huguier  transmits  chorda  tympani  nerve; 

Foramen  for  Jacobsons  nerve,  the  tympanic  branch  of  the 
glossopharyngeal  nerve ; 

Foramen  for  Arnold's  nerve,  the  auricular  branch  of  the 
pneumogastric  nerve ; 

Opening  of  aquaductus  cochlea  transmits  a  vein  from  the 
cochlea  to  internal  jugular  vein; 

Auricular  fissure  gives  exit  to  Arnold's  nerve; 

Stylomastoid  foramen  transmits  the  facial  nerve  and  stylo- 
mastoid artery. 

Anterior  region  presents  three  pairs: — 

Supraorbital  foramen,  or  notch,  transmits  supraorbital  ar- 
tery, vein  and  nerve; 


OSTEOLOGY. 


51 


Fie     31. 
8t<  rnum  and  costal  <artilages. 


52  HUMAN    ANATOMY. 

Infraorbital  foramen  transmits  infraorbital  artery  and 
nerve,  and 

Mental  foramen  transmits  mental  nerve  and  artery. 

BONES    OF    THE    TRUNK. 

The  sternum,  or  breast  bone,  is  a  long,  narrow,  sword-like 
bone  occupying  the  anterior  part  of  the  thorax  and  consisting 
of  three  portions:  manubrium  (manubrium  sterni  or  pre- 
sternum— handle),  gladiolus  (mesosternum  or  corpus  sterni — 
blade),  xyphoid  or  ensiform  appendix  (processus  xiphoideus  or 
metasternum — point).  Its  anterior  surface  is  irregularly  flat, 
posterior  surface  slightly  concave. 

Manubrium  sterni  (presternum)  is  thick  and  triangular, 
and  presents  above  the  interclavicular  notch,  on  either  side  of 
which  are  facets  for  articulation  of  clavicles.  Laterally  it  pre- 
sents an  articular  facet  for  the  cartilage  of  the  first  rib  and  a 
half  facet  for  part  of  second  costal  cartilage. 

Gladiolus  or  corpus  sterni  (mesosternum)  is  the  longest, 
narrowest  portion  and  presents  about  its  center,  between  the 
third  and  fourth  segments,  the  sternal  foramen,  laterally  facets 
for  half  of  the  second  and  for  the  third,  fourth,  fifth  and  sixth 
costal  cartilages. 

Ensiform  appendix  (processus  xiphoideus  or  metasternum) 
is  cartilaginous  in  youth  and  varies  much  in  size  and  shape. 

It  articulates  with  the  clavicles  and  seven  costal  cartilages 
on  side. 

Its  ossiflc  centers  are  six — one  each  for  the  manubrium  and 
appendix  and  four  for  the  gladiolus,  or  body. 

Its  muscular  attachments  are  ten— sternomastoid,  sterno- 
hyoid, sternothyroid,  pectoralis  major,  triangularis  sterni,  ob- 
liquus  externus  and  interims,  transversalis,  rectus  and  dia- 
phragm. 

The  ribs  (costce),  twelve  on  each  side,  form  a  series  of  nar- 
row elastic  arches  on  each  side  of  the  thorax,  constituting  the 
chief  part  of  the  thorax.  They  are  divided  into  seven  vertebro- 
sternal, true  or  sternal  ribs  (costce  vera.),  each  of  which  joins  the 
sternum  by  a  separate  costal  cartilage;  three  vertebrochondral, 
or  false  (costm  spurice),  the  cartilages  of  which  join  each  other 
and  with  the  seventh  before  uniting  with  the  sternum,  and  two 
vertebral,  free  or  floating,  which  have  no  sternal  attachment. 

Each  rib  consists  of  a  head,  neck,  tubercle  and  body. 

The  head  (capitulum  costm)  presents  facet  (except  the  first, 
tenth,  eleventh  and  twelfth)  for  articulation  with  the  bodies  of 


OSTEOLOGY. 


53 


the   contiguous   dorsal   vertebra1,,  separated  by   a   ridge    (crista 
capituli)  for  the  interartienlar  ligament. 

The  neck  (collum  costce)  or  constricted  portion  is  smooth 
in  front  and  presents  a  rough  surface  behind  for  the  middle  cos- 
totransverse ligament  and  a  rough  crest  (crista  colli  costce) 
above  for  the  anterior  costotransverse  ligament. 


Sfifjttfy 


Sinjh  urttcular  faett  — 


SinyU  »rtit.  /Lett  — 


Jinglt    artit.  fae. 


Fig.  32. 
The  peculiar   ribs. 


The  tubercle  or  tuberosity  (tuberculum  costce)  (wanting  in 
eleventh  and  twelfth),  presents  an  articular  surface  (fades  art ic- 
ularis  tuberculi)  for  articulation  with  the  transverse  process  of 
the  vertebra  below,  and  a  non-articular  surface  foT  attachment 
of  the  posterior  costotransverse  ligament. 


54  HUMAN    ANATOMY. 

The  shaft  or  body  (corpus  costce)  is  flat,  thin  and  twisted 
on  itself.  Its  anterior  extremity  presents  an  oval  depression  for 
costal  cartilage. 

The  internal  surface  is  smooth,  concave,  and  presents  in 
front  of  the  angle  a  ridge,  forming  the  side  of  the  groove  on  the 
inferior  border. 

The  external  surface  is  rough,  convex  and  presents  a  little 
in  front  of  the  tubercle,  a  bend  or  angle  (angulus  costce)  marked 
by  a  prominent  line,  and  near  the  sternal  extremity  another 
bend,  the  anterior  angle,  marked  by  an  oblique  line. 

The  superior  border^  is  round  and  thick  and  presents  an 
external  and  internal  lip  for  external  and  internal  intercostal 
muscles. 

The  inferior  border,  at  its  posterior  third,  presents  a  groove 
(sulcus  costai)  for  the  intercostal  vessels  and  nerve,  and  at  its 
anterior  two-thirds  is  sharp  and  thin. 

Peculiar  Ribs. — The  peculiar  ribs  are  the  first,  second, 
tenth,  eleventh  and  twelfth. 

The  first  is  short,  broad,  has  no  angle,  and  but  one  facet 
on  the  head.  Its  upper  surface  is  marked  by  two  parallel 
grooves,  the  anterior  for  the  subclavian  vein,  the  posterior  for 
the  artery  separated  by  a  tubercle  (tubercidum  scaleni)  for  in- 
sertion of  scalenus  anticus  muscle, — an  important  guide  in  liga- 
tion of  the  subclavian  artery. 

The  second  resembles  the  first  in  being  flattened  and  not 
twisted.  The  tubercle  and  angle  are  slight  and  almost  coincide 
in  position.  The  outer  surface  of  the  shaft  presents  near  its 
middle  a  rough  eminence  for  the  second  and  third  portions  of  the 
serratus  magnus. 

The  tenth  rib  has  but  one  facet  for  articulation  with  the 
tenth  dorsal  vertebra. 

The  eleventh  has  single  facet  on  head,  slight  angle,  but  no 
tubercle  or  neck. 

The  twelfth,  single  facet,  but  no  angle,  tubercle,  or  neck. 

The  ribs  articulate  with  twelve  vertebrae  behind  and  twelve 
costal  cartilages  in  front. 

Muscular  attachments  are  twenty — scalenus  anticus,  medius 
and  posticus,  pectoralis  minor,  intercostals,  serratus  magnus,  ob- 
liquus  externus,  transversalis,  quadratus  lumborum,  diaphragm, 
latissimus  dorsi,  serratus  posticus,  superior  and  inferior;  sacro- 
lumbalis,  musculus  accessorius  ad  iliocostaleni,  levatores  costa- 
rum,  longissimus  dorsi,  cervicalis  ascendens,  and  infracostales. 

Each  rib  has  one  center  for  its  head,  shaft  and  tubercle, 
except  the  eleventh  and  twelfth,  which  have  but  two  centers, 
that  for  the  tubercle  being  wanting. 


OSTEOLOGY. 


55 


O 

c 

2- 

•3 


Fio.  33. 
The  vertebral  column,   or  spine. 


56 


HUMAN    ANATOMY. 


VERTEBRA. 

The  spine,  or  vertebral  column  (columna  vertebralis) , 
is  a  flexible  column  composed  of  twenty-six  bones  ( thirty- three 
vertebrae),  as  follows:  seven  cervical,  twelve  dorsal,  five  lumbar, 
sacrum  and  coccyx.  Each  vertebra  consists  of  a  body  or  cen- 
trum (corpus  vertebrae),  and  an  arch  (arcus  vertebra),  com- 
posed of  two  pedicles  and  two  laminae,  supporting  seven  processes 
— one  spinous,  two  transverse  and  four  articular. 

The  body  (centrum — corpus  vertebra),  the  large,  solid, 
anterior  portion,  is  generally  half-cylindrical,  concave  behind, 
convex  in  front  and  sides.     Its  upper  and  lower  surfaces  are 


ffiuftrui?  Artie,  true, 


Demi  .facet  tor  /lead  of  Rib 


Taeet^r  Tuhnh  of  Sib 


Demijacetfir7ua.il  of  Rih 
Infer.  Artie.  Proe* 


Fig.  34. 
A  dorsal  vertebra. 

broad  and  rough,  for  attachment  of  interarticular  cartilages. 
Its  posterior  surface  has  large  foramen  for  exit  of  veins. 

The  pedicles  (radix  arcus  vertebra)  project  backward  (ex- 
cept the  cervical,  which  project  obliquely  outward),  and  present 
four  intervertebral  notches  (incisura  vertebralis  superior  et  in- 
ferior), two  each,  above  and  below.  These,  when  articulated, 
form  interarticular  foramina  (foramina  intervertebral)  for 
exit  of  spinal  nerves  and  passage  of  blood-vessels. 

The  lamina  are  two  broad,  flat  plates  of  bone,  projecting 
backward  and  inward  from  the  pedicles  to  complete  the  verte- 
bral arch  and  inclose  the  spinal  foramen.  Their  upper  and 
lower  margins  are  rough  for  attachment  of  the  ligamenta  sub- 
flava. 

The  spinous  processes  vary  much  in  size  and  shape  in  the 
different  regions.  .They  project  backward  from  the  junction 
of  the  laminae  and  afford  attachment  for  muscles. 


OSTEOLOGY. 


57 


The  transverse  processes  (processus  transversi)  project  one 
on  each  side,  from  the  junction  of  the  laminae  with  the  pedicles. 
•and  in  the  cervical  region  from  the  sides  of  the  body  also,  in- 
closing the  foramen  for  the  vertebral  artery. 


AiiUritrTubircli  of  TraniTrtc. 

lorami*  f„  Virttbrtl  Art  *. 

fortrirrTulcrtlt  *f  TrantPi 


rdiavertc  JPtvc/sa 


JUP/fiOT-  Articular  PmH& 
nfcrwrAlticular  SractO 


Fig.  35. 
A  cervical  vertebra. 


The  articular  processes  (zygapophyses) ,  four  in  number, 
project  one  above  and  below  on  each  side,  from  the  junction  of 
the  lamina  and  pedicles.  The  two  superior  (processus  articu- 
lar /'.-■  superior)   project  upward  and  more  or  less  backward,  the 


Tuberc/f 


Trani.Proc, 


J" or  am -a  /or 
Vertebral ArtX 


'ovefer  Vert  of.  Art  J 
and  1"  Cerv.Norva 


inferior  (processus  arlicu/aris  inferior)  downward  and  more  or 
lese  forward,  articulating  with  the  corresponding  processes  of 
the  adjoining  vertebra. 

The  Bpinal   foramen    (foramen  vertebrate)    is  a   large,  tri- 
angular canal,  inclosed  by  the  body  in  front,  the  pedicles  later 
ally  and  the  lamina'  behind,  f<»r  the  passage  of  the  spinal  cord 
and  it-  membranes. 


58  HUMAN    ANATOMY. 

The  ceevical  vertebra  (vertebrce  cervicales)  are  char- 
acterized by  small  body,  concave  above,  convex  below,  the  an- 
terior margin  overlapping  the  one  below;  short  and  bifid  trans- 
verse process,  perforated  at  base  by  foramen  for  vertebral  artery  : 


Artie.  Surf.firJUU* 


Gb&tfove, 


Treni.frcf 

Fig.  37. 
The  axis. 


oblique  articular  processes — superior  convex  directed  upward  and 
backward,  inferior  concave  downward  and  forward;  short  spin- 
ous process,  bifid,  placed  horizontally;  long  and  narrow  lamina, 
inclosing  large,  triangular  spinal  canal  (canalis  vertebralis) . 


Fig.  38. 
Seventh  cervical,  or  vertebra  prominens. 

The  peculiar  cervical  vertebrce  are  first,  second  and  seventh. 

The  first  or  atlas  is  ring-like,  without  either  body  or  spinous 
process,  and  consists  of  an  anterior  arch  (arcus  anterior),  a 
posterior  arch  (arcus  posterior)  and  two  lateral  masses  (massce 
laterales).  The  anterior  arch,  convex  in  front,  presents  tubercle 
for  longus  colli  muscles  and  behind  articulates  with  odontoid 


OSTEOLOGY. 


59 


process  of  axis.    The  ggstejioT  arch  is  deeply  grooved  above  for 

transmission  of  vertebral  artery  and  suboccipital  nerves  and 
terminates  behind  in  a  rudimentary  spine.  It  articulates  above 
with  condyles  of  occipital,  below  with  axis.  The  transverse 
process  is  short  and  contains  a  foramen. 

The  axis  (epistropheus),  so  called  from  the  pivot-like  odon- 
toid process  (dens),  which  projects  from  the  upper  part  of  its 
hodv  to  articulate  with  the  anterior  arch  and  transverse  ligament 
of  atlas. 


*nnr*/tu*t 
"fir  Artie fm. 


Fig.  39. 
Peculiar   dorsal   vertebrae. 


The  seventh  resembles  the  dorsal  series;  its  spinous  process 
being  long,  not  bifid,  and  prominent;  bence  its  name,  "vertebra 
|.roiiiiii<-ii-.'"    To  ii  is  attached  die  ligamentum  nucha1. 

Tin:  i)oi;s.\i>  vi:i;ti;i:i;.i-;  (vertebra  thoracales)  have  large, 
lie;irt-.dia|icd  bodies,  Hat  above  and  below.  Laterally  have  demi- 
articular  facets  (fovea  costalis  superior  et  inferior)  for  heads 
of  ribs;  long,  strong,  transverse  processes,  marked  by  Facel  for 
tubercle  of  rib  (fovea  costalis  vertebralis) ;  vertical  articular 
processes,  superior  backward,  inferior  forward;  long,  triangular, 
overlapping  spinous  proems;  small,  and  nearly  circular,  spinal 
canal. 


60 


HUMAN    ANATOMY. 


The  peculiar  dorsal  vertebra?  are :  first,  which  resembles 
cervical,  and  has  distinct  facet  for  head  of  first  rib,  and  half- 
one  for  half  of  second  head;  tenth,  eleventh  and  twelfth;  one 
facet  for  head  of  rib;  and  eleventh  and  twelfth,  no  facet  on 
transverse  processes  for  tubercle  of  rib. 

The  lumbar  vertebra  (vertebra?  lumbales)  are  the 
largest,  and  have  transverse  oval  body,  flat  above  and  below; 
long,  thin,  transverse  processes,  representing  ribs;  vertical  proc- 
esses interlocking  with  adjacent  vertebrae;  large,  triangular 
spinal  canal. 

The  last  lumbar  is  peculiar  in  having  body  thicker  in  front, 
shorter  and  stronger  transverse  process,  and  inferior  articular 
processes  wider  apart,  and  directed  forward. 


Super.  Artie.  Proc. 


Fig.  40. 
A  lumbar  vertebra. 


Muscular  attachments  to  atlas,  ten — rectus  anticus  minor, 
rectus  lateralis,  rectus  posticus  minor,  obliquus  superior  and 
inferior,  splenius  colli,  levator  anguli  scapulas,  interspinous  and 
intertransverse.  To  axis,  ten — the  last  five  of  preceding,  and 
obliquus  inferior,  rectus  posticus  major,  semispinalis  colli,  mul- 
tifidus  spinas,  scalenus  posticus  and  transversalis  colli. 

To  the  remaining  vertebras  are  attached  anteriorly  ten  (10) 
muscles,  and  posteriorly  twenty- two  (22)  [vide  Spinal  Muscles, 
p.  107]. 

Development. — The  ossific  centers  for  each  vertebra  are 
three  primary,  one  for  the  body  and  one  for  each  side,  and  five 
secondary  epiphyses,  as  follows :  one  for  tip  of  each  spinous  and 
transverse  process,  and  the  remaining  two  are  thin  plates,  on 
articular  surfaces. 

The  exceptions  to  this  rule  are :  atlas,  with  two  primary 
centers  and  one  epiphysis ;  the  axis,  with  three  extra  centers  for 


OSTEOLOGY. 


61 


odontoid  process;  the  seventh  cervical,  with  one  extra  center  for 
each  transverse  process,  and  the  lumhar  vertebras,  two  additional 
centers  for  tubercles. 

The  sackum  (os  sacrum)  is  a  large,  wedge-shaped  bone, 
base  above,  apex  below,  with  expanded  lateral  masses  and  alse, 
composed  of  five  consolidated  sacral  vertebra?,  and  forming  the 
posterior  wall  of  pelvis. 

The  base  (basis  oss.  sacri)  articulates  with  the  last  lumbar 
vertebra.     Its  anterior  edge  forms  the  promontory  or  sdcrover- 


FromontoTy 


Fig.  41. 
The  sacrum,   anterior  surface. 


tebral  angle  (promontoriam)  on  each  side  of  which  is  a  smooth 
triangular  surface,  the  ala  (ala  sacral  is).  Behind  the  artic- 
ulating surface  is  the  sacral  canal  (canalis  sacfaUs),  ami  on 
either  side  are  the  superior  processes. 

The  apex  (apex  oss.  sacri)  is  small  and  articulates  with  the 
coccyx. 

The  anterior  concave  surface  (fades  pelvina)  presents  four 
ridges  (lineaz  transversa;)  indicating  the  original  separations, 
which   terminate  externally   in  eight    anterior  sacral    foramina 

(foramina  SOCralia  anlcrinra  ) .  with  wide,  shallow  i/ronrcs,  for 
the  exit  of  the  anterior  sacral  nerves.  To  the  outer  side  of  these 
foramina  i-  the  lateral  mass  (pars  lateralis)  for  origin  of  pyri- 
formifl  muscle. 


62 


HUMAN    ANATOMY. 


The  posterior  surface  (fades  dor  sails)  presents  rudimen- 
tary spinous  articular  and.  transverse  processes,  the  lamina?  of 
the  last  two  segments  being  deficient.1  On  the  other  side  of  the 
spinous  process  is  a  broad,  shallow  concavity,  the  sacral  groove, 
for  the  origin  of  the  erector  spinse  muscle,  and  external  to  the 
articular  processes  are  four  posterior  sacral  foramina  (foramina 
sacralia  posteriora)  for  the  exit  of  posterior  sacral  nerves. 

The  lateral  surfaces  have  each  a  rough  articular  surface  for 
articulation,  with  ossa  innominata,  and  below  presents  a  deep 


Pig.  42. 
The  sacrum,  posterior  surface. 


notch  on  each  side  of  the  apex,  which  is  converted  by  articulation 
with  the  transverse  process  of  the  coccyx  into  the  fifth  sacral 
foramen,  for  exit  of  anterior  division  of  the  fifth  sacral  nerve. 

The  sacral  canal  (canalis  sacralis),  continuous  above  with 
the  spinal  foramen  of.  the  vertebrae,  runs  through  the  center. 
Large  and  triangular  above,  small  and  flattened  below,  its  lower 
posterior  wall  is  deficient  (hiatus  sacralis).  It  lodges  the  sacral 
nerves,  and  out  of  it  pass  the  anterior  and  posterior  sacral 
foramina. 


i  The  articular  processes  of  the  fourth  and  fifth  unite  to  form  the 
sacral  cornua  for  articulation  with  the  cornua  of  the  coccyx. 


OSTEOLOGY.  (53 

It  articulates  with  four  bones, — two  os,sa  innominata,  last 
lumbar  vertebra  and  coccyx. 

Muscular  attachments  are  seven — iliacus,  piriformis,  coc- 
cygeus,  gluteus  niaximus,  latissimus  dorsi,  multifidus  spinae  and 
erector  spina?. 

Its  ossific  centers  are  thirty-five,  as  follows:  bodies,  includ- 
ing interarticular  plates,  three  each  (15)  ;  arches,  two  each  (10)  ; 
lateral  masses,  six  (6)  ;  epiphyseal  plates  of  lateral  surfaces, 
four  (1).     Total,  35. 

The  coccyx  (os  coccygis)  is  a  small' triangular  bone,  re- 
sembling a  cuckoo's  beak,  and  composed  of  four  rudimentary 
vertebra?  more  or  less  co-ossified  (vertebra  coccygece). 

•The  base  articulates  with  the  sacral  apex,  being  prolonged 
upward  into  two  cornua  to  complete  the  fifth  posterior  sacral 
foramen  for  exit  of  posterior  Branch  of  fifth  sacral  nerve. 

Laterally  the  base  is  prolonged  into  rudimentary  transverse 
processes,  completing  with  the  notch  of  the  sacrum  the  fifth 
anterior  sacral  foramina  for  exit  of  the  anterior  branch  of  fifth 
sacral  nerve. 

The  anterior  concave  surface  supports  the  rectum  and  gives 
attachment  to  levator  ani  muscle  and  anterior  sacrococcygeal 
ligament. 

The  posterior  convex  surface  presents  rudimentary,  artic- 
ular processes  and  transverse  grooves. 

The  apex  is  roimded,  occasionally  bifid,  or  deviated  to  one 
side,  and  affords  attachment  to  the  levator  ani  and  sphincter 
ani  muscles. 

The  muscular  attachments  are  coccygei,  gluteus  maximus, 
extensor  coccygeus  (occasionally  present),  levator  and  sphincter 
ani. 

Its  ossific  centers  are  four — one  for  each  segment. 

THE  UPPER  EXTREMITY. 

The  upper  extremity  consists  of  the  arm,  forearm  and 
hand.  It  is  attached  to  the  trunk  by  the  shoulder-girdle  formed 
by  the  clavicles,  and  scapulae  and  contains  the  following  bones: 
Clavicle,  scapula,  humerus,  radius,  ulna,  eight  carpus,  five  meta- 
carpus and  fourteen  phalanges. 

Tin:  CLAVICLE  (clavicula) ,  or  collar-  or  key-  bone,  is  a  long 
bone,  curved  horizontally  like  the  italic  letter  /,  extending  almost 
horizontally  between  the  sternum  and  acromial  process  of  scap- 
ula. Its  inner  two-thirds  are  cylindrical  and  convex  in  front,  its 
outer  third  flattened  from  above  downward  and  concave  in  front. 


64  HUMAN    ANATOMY. 

It  consists  of  a  body,  or  shaft,  and  outer,  or  acromial,  and 
inner,  or  sternal  extremities. 

The  shaft  presents  in  its  outer  third  the  following  points : — 

Superior  surface,  rough  impression  in  front  for  deltoid  mus- 
cle, rough  impression  behind  for  trapezius; 

Anterior  border,  occasionally  deltoid  tubercle  about  the 
center  for  attachment  of  deltoid; 

Inferior  surface,  conoid  tubercle  (tuberositas  coracoidea) 
at  the  posterior  border  for  conoid  ligament;  oblique  line  ex- 
tending outward  and  forward  from  this  for  attachment  of 
trapezoid  ligament. 

The  inner  two-thirds  is  prismatic  and  presents  three  sur- 
faces and  three  borders: — 

AeraLiiulUxtV 

Si 'e  mih  t  Ej.-tr 


FIG.  43. 
The  left  clavicle,   upper  surface. 

Anterior  surface,  divided  by  line  into  upper  rough  surface 
for  sternomastoid  muscle  and  lower  for  pectoralis  major; 

Posterior  or  cervical  surface  gives  attachment  to  sterno- 
hyoid muscle  and  presents  foramen  (foramen  nutricium)  for 
nutrient  artery. 

Inferior  or  subclavian  surface  presents : — 

Facet,  continuous  with  sternal  articular  surface,  for  car- 
tilage of  first  rib ; 

Rhomboid  impression  (tuberositas  costalis)  for  costoclavic- 
ular or  rhomboid  ligament; 

Subclavian  groove  for  attachment  of  subclavian  muscle; 

Longitudinal  line,  frequently  dividing  the  groove  into  two 
parts,  for  intermuscular  septum  of  the  muscle. 

Anterior  border  separates  the  anterior  and  posterior  sur- 
faces and  limits  the  attachment  of  the  pectoralis  major. 

Superior  border  gives  attachment  to  the  sternomastoid 
muscle. 

Posterior  or  subclavian  border  is  short  and  concave,  extend- 
ing from  the  rhomboid  impression  to  the  conoid  tubercle  and 
giving  attachment  to  the  subclavian  fascia. 


OSTEOLOGY. 


65 


The  acromial  extremity  {ex/ rem  Has  acromialis)  presents  an 
oval  facet  (fades  articularis  acromialis)  for  articulation  with 
the  acromial  process  of  the  scapula  and  a  rough  circumference 
for  acromioclavicular  ligaments. 

The  sternal  extremity  (extremitas  sternalis)  is  triangular, 
and  presents  a  facet  (fades  articulans  sternalis)  for  cartilage 
of  sternal  articulation  and  rough  circumference  for  sternoclavic- 
vdar  ligaments. 

The  clavicle  articulates  with  three  hones — the  sternum, 
scapula,  and  first  costal  cartilage. 

The  muscular  attachments  are  seven — subclavius,  platysma, 
sternohyoid,  sternomastoid,  trapezius,  pectoralis  major  and  del- 
toid. 


Fig.  44. 
The   left  clavicle,   under   surface. 


end. 


Its  ossific  centers  are  two — one  each  for  bodv  and  sternal 


The  scapula,  or  shoulder  Hade,  is  a  large,  flat,  triangular 
bone  situated  on  the  upper  posterolateral  aspect  of  the  thorax 
from  the  second  to  seventh  rib,  inclusive. 

It  consists  of  a  body,  head,  neck,  acromion  and  coracoid 
processes,  and  presents  two  surfaces,  three  borders,  and  three 
angles. 

The  anterior  surface,  venter  or  costal  surface  (fades  cos- 
tal is)  presents: — 

Subscapular  fossa  (fossa  subscapularis) ,  a  concave  tri- 
angular surface  for  attachment  of  subscapular  muscles, 
marked  by 

Oblique  ridges  (linen'  musculares)  for  the  tendinous  inter- 
sections of  the  muscle  ; 

Marginal  warfare,  for  attachment  of  serratus  magnus; 

Subscapular  angle  (angvlus  subscapularis) ,  a  transverse 
depression  at  the  upper  pari  for  the  thickest  pari  <>r  the  muscle. 

The  posterior  surface,  or  dorsum  (fades  dorsalis), 
presents : — 

5 


66 


HUMAN    ANATOMY. 


Spine  (spina  scapulae),  a  bony  ridge  passing  upward,  for- 
ward, and  outward,  dividing  it  unequally  into  two  fossae,  afford- 
ing attachment  to  the  trapezius  muscle  above  and  the  deltoid 
below,  and  terminating  above  in  the  acromion  process; 

Supraspinous  fossa  (fossa  supraspinata)  above  the  spine, 
for  the  origin  of  the  supraspinatus  muscle; 

Infraspinous  fossa  (fossa  infraspinata)  below,  for  the 
origin  of  the  infraspinatus  muscle; 


Fig.  45. 
The  scapula,   anterior  surface. 

Nutrient  foramen,  near  the  upper  part  of  the  infraspinous 
fossa,  for  nutrient  artery. 

The  marginal  surface  extends  from  the  glenoid  cavity  down- 
ward and  backward  to  an  inch  above  inferior  angle,  its  inner 
side  formed  by 

An  elevated  ridge,  for  the  attachment  of  the  aponeurosis 
between  the  infraspinatus  and  two  teres  muscles;  its  outer  side 


OSTEOLOGY. 


67 


by  the  axillary  border.  It  is  divided  by  an  oblique  line  into  two 
parts,  the  upper  for  the  teres  minor  and  the  lower  for  the  teres 
major  muscles,  and  crossed  by  a  groove  near  the  upper  part  for 
the  dorsalis  scapulas  vessels; 


>*'/ 


Co  r a  cot' & 


Fir,.  46. 
The  scapula,    posterior  surface. 


A  smooth,  triangular  surface  at  the  root  <>f  the  spine  over 

which  the  trapezius  glides. 

The  superior  border  (marf/o  superior),  shortest,  presents: — 
Suprascapular  ootch   (incisura  scapula')  at  the  base  of  the 

coracoid   process,  converted   into  a  foramen   [suprascapular]   by 

the  transverse  ligament,   for  the  passage  of  the  suprascapular 

nerve  ( the  artery  passing  above)  ; 


08  HUMAN    ANATOMY. 

Origin  of  omohyoid  muscle  from  this  border  just  internal 
to  notch. 

External  or  axillary  border  (mar go  axillaris),  thickest, 
presents : — 

Eough  impression,  the  infraglenoid  tubercle  (tuberositas 
infraglenoidalis),  just  below  glenoid  cavity,  for  origin  of  long 
head  of  triceps  muscle,  and  below 

Longitudinal  groove,  for  origin  of  part  of  subscapulars. 

Internal,  veretebral  border — base  (mar go  vertebralis) ,  long- 
est, presents : — 

Anterior  lip,  for  insertion  of  serratus  magnus; 

Posterior  lip,  for  attachment  above  of  supraspinatus,  below 
infraspinatus. 

•The  superior  angle  (angulus  medialis)  gives  attachment  to 
part  of  levator  anguli  scapulas; 

The  inferior  angle  (angulus  inferior),  for  attachment  of 
teres  major,  and  sometimes  part  of  latissimus  dorsi. 

The  anterior  or  external  angle  (angulus  lateralis)  is  thick- 
est, and  forms  the  head. 

The  head  is  connected  to  the  body  of  the  scapula  by  a  con- 
stricted portion,  the  neck  (collum  scapulae),  from  the  anterior 
surface  of  which  arises  the  coracoid  process.     It  presents 

The  glenoid  cavity  or  fossa  (cavitas  glenoidalis) ,  a  shallow, 
pyriform,  articular  depression,  deepened  in  the  recent  state  by 
the  glenoid  ligament,  for  the  head  of  the  humerus.  To  its  upper 
part  or  apex  is  attached  the  long  head  of  the  biceps  muscle. 

The  acromion  process  (acromion),  forming  the  summit 
of  the  shoulder,  is  a  triangular  process,  projecting  forward,  out- 
ward and  upward,  to  overarch  the  glenoid  cavity.  It  gives  at- 
tachment by  its  upper  surface  to  the  platysma  and  deltoid  and 
by  its  inner  margin  to  the  trapezius.     It  presents 

An  apex,  for  attachment  of  coracoacromial  ligament; 

Articular  facet,  just  behind  the  apex  for  the  clavicle. 

The  coracoid  process  (processus  coracoideus) — like  a 
crow's  beak — arches  forward,  upward,  and  inward  above  the 
glenoid  cavity.     It  presents 

Attachment  for  pectoralis  minor  muscle  from  the  anterior 
border  near  the  tip; 

Apex,  for  attachment  of  coracobrachialis  and  short  head  of 
biceps ; 

Rough  impression  at  the  inner  side  of  the  root  for  the 
conoid  ligament,  and  from  it 

A  ridge  running  outward  and  forward  for  the  trapezoid 
ligament. 


OSTEOLOGY. 


69 


r--.a 


FIQ.  47. 

The  humerus,   anterior 
surface. 


Fig.  48. 

The  humerus,   posterior 
surface. 


70  HUMAN    ANATOMY. 

It  articulates  with  the  clavicle  and  humerus. 

Its  muscular  attachments  are  18 :  platysma,  supra-  and 
infra-  spinatus,  subscapular,  deltoid,  trapezius,  omohyoid,  ser- 
ratus  magnus,  levator  anguli  scapulge,  rhomboideus  major  and 
minor,  triceps,  teres  major  and  minor,  biceps,  coracobrachialis, 
pectoralis  minor  and  latissimus  dorsi. 

Its  ossific  centers  are  seven — one  each  for  body,  posterior 
border,  and  inferior  angle,  and  two  each  for  acromion  and  cora- 
coid  processes. 

The  humerus,  or  arm  bone,  the  largest  and  longest  bone 
of  the  upper  extremity,  consists  of  a  shaft,  head,  neck,  greater 
and  lesser  tuberosities  and  lower  extremity. 

The  shaft  (corpus  humeri),  cylindrical  above,  flattened  and 
prismoid  below,  becomes  twisted  in  the  middle,  and  presents 

A  rough  triangular  surface  about  the  middle  of  its  outer 
surface  (tuberositas  deltoidea)  for  insertion  of  the  deltoid 
muscle,  and  a 

Musculo  spiral  groove  for  the  musculospiral  nerve  and  supe- 
rior profunda  artery,  on  each  side  of  which  arise  the  external  and 
internal  heads  of  the  triceps  muscle. 

The  upper  extremity  presents 

The  head  (caput  humeri)  forming  nearly  a  sphere,  project- 
ing upward,  backward  and  inward,  articulating  with  the  glenoid 
cavity ; 

The  anatomical  neck  (collum  anatomicum) ,  immediately 
beneath,  is  slightly  grooved  for  the  attachment  of  the  capsular 
ligament ; 

Greater  tuberosity  (tuherculum  ma-jus),  external  to  the 
head  and  lesser  tuberosity,  with  three  facets  from  before  back- 
ward for  attachment  of  supraspinatus,  infraspinatus  and  teres 
minor  muscles; 

Lesser  tuberosity  (tuherculum  minus),  smaller  but  more 
prominent  than  greater,  is  anterior  to  head,  for  the  subscajmlar 
muscle ; 

Bicipital  groove  (sulcus  intertubercularis) ,  passes  down- 
ward and  inward  between  the  two  tuberosities  and  lodges  the 
long  tendon  of  biceps; 

The  anterior  bicipital  ridge  (crista  tuberculi  minoris), 
bounds  the  groove  in  front  and  receives  insertion  of  pectoralis 
major  muscle; 

The  posterior  bicipital  ridge  (crista  tuberculi  majoris),  re- 
ceives the  latissimus  dorsi  and  teres  major; 

The  surgical  neck  (collum  chirurgicum) ,  including  the 
head,  neck  and  both  tuberosities; 


OSTEOLOGY.  71 

A  rough  impression  near  the  center  of  the  inner  border  for 
the  coracobrachial  muscle ; 

Nutrient  canal,  below  and  directed  toward  the  lower  ex- 
tremity. 

The  lower  extremity  presents  from  within  outward  the  fol- 
lowing1 : — 

Internal  condyloid  ridge,  extending  upward  from  the  con- 
dyle ; 

Internal  condyle  or  epicondyle  (epicondylus  medialis), 
more  prominent  than  external,  gives  origin  to  the  flexors  and 
pronator  radii  teres; 

EpitrocMea,  an  eminence  separating  the  trochlea  from  the 
internal  condyle; 

Trochlea  {trochlea  humeri)  a  pulley-like  articulating  sur- 
face for  greater  sigmoid  cavity  of  ulna; 

Coronoid  fossa  (fossa  coronoidea)  a  small  depression  bound- 
ing the  trochlea  in  front,  and  receiving  the  coronoid  of  the  ulna 
in  flexion ; 

Olecranon  fossa  (fossa  olecrani),  a  larger  depression  behind, 
and  receiving  the  olecranon  process  of  ulna  in  extension; 

Supratrochlear  foramen,  sometimes  formed  by  perforation 
of  one  fossa  into  the  other; 

Radial  head,  or  eapitellum  (capitulum  humeri),  a  smooth, 
rounded  eminence  articulating  with  cup-like  depression  on  head 
of  radius : 

External  condyle  or  epicondyle  (epicondylitis  lateralis),  less 
prominent,  gives  origin  to  the  extensors  and  supinators; 

External  condyloid  ridge,  extending  upward  on  the  shaft 
from  the  condyle. 

It  articulates  with  three  bones — scapula,  radius  and  ulna. 
Its  muscular  attachments  are  twenty-five — subscapulars, 
supra-  and  infra-  spinatus,  teres  major  and  minor,  pectoralis 
major,  latis&imns  dorsi,  deltoid,  coraeobrachialis,  brachialis  an- 
ticus,  triceps,  pronators  and  flexors  to  inner  condyle,  pronator 
radii  teres.,  flexor  carpi  radialis,  palmaris  Longus,  flexor  sublimus 
digitorum,  flexor  carpi  ulnaris,  supinators  and  extensors  to  outer 
condyle,  supinator  Longus,  extensor'  carpi  radialis  longior  and 
brevior,  extensor  communis  digitorum,  extensor  minimi  digiti. 


i  Some  confusion  exists  in  anatomical  works  because  of  the  loose. 
employment  of  the  terms  condyle,  epicondyle,  ami  epitrochlear.  tt 
should  lie  borne  in  mind,  however,  thai  many  anatomists  use  Hie  terms 
external  condyle  and  external  epicondyle  synonymously,  while  others 
designate  the  inner  condyle  ;i-  the  internal  epicondyle  or  epitrochlea. 


72  HUMAN    ANATOMY. 

extensor  carpi  ulnaris,  anconeus  and  subanconeus,  supinator 
brevis. 

Its  ossific  centers  are  seven — one  each  for  head,  shaft,  tu- 
berosities, condyles,  radial  head,  and  trochlear  portion. 

The  ulna,  or  elbow  bone,  is  a  long  bone  to  the  inner  side 
of  the  forearm,  and  consists  of  a  shaft  and  an  upper  and  lower 
extremity.  It  forms  the  greater  part  of  the  articulation  with  the 
humerus,  but  does  not  enter  into  the  formation  of  the  wrist- 
joint,  being  excluded  by  the  interarticular  fibrocartilage. 

The  shaft  (corpus  ulnce)  is  prismatic  above,  smooth  and 
rounded  below,  and  presents : — 

Anterior  or  palmar  surface  (fades  volaris),  gives  attach- 
ment to  the  deep  flexors  and  pronator  quadratus; 

Nutrient  foramen  (foramen  nutricium)  on  anterior  sur- 
face, directed  upward  toward  the  elbow-joint; 

Posterior  or  dorsal  surface  (faeies  dorsalis)  marked  above 
by  an  oblique  line  for  part  of  supinator  brevis,  above  which  is 
smooth  triangular  surface  for  anconeus  muscle,  and  the  lower 
third  for  extensor  muscles  of  the  thumb; 

External  or  interosseous  border  (crista  inter ossea) ,  sharp 
in  middle  two-thirds,  for  attachment  of  interosseus  membrane. 

The  upper  extremity  is  large  and  irregular,  and  presents : — 

Olecranon  process  (olecranon — head  of  elbow),  projects 
upward  and  forward,  its  apex  being  received  into  the  olecranon 
fossa  of  the  humerus  in  extension  of  the  forearm;  its  upper 
border  has  rough  impression  for  the  triceps  muscle;  its  lateral 
borders  are  grooved  for  external  and  internal  lateral  ligaments; 

Coronoid  process  (processus  coronoicleus) ,  smaller  than 
olecranon,  projects  forward  from  anterior  surface,  being  re- 
ceived into  coronoid  fossa  of  humerus  in  flexion. 

Its  upper  surface  forms  part  of  the  great  sigmoid  cavity. 

Its  under  surface  has  rough  impression  for  insertion  of 
brachialis  anticus,  and  has,  at  its  junction  with  the  shaft,  the 
tubercle  of  the  ulna  (tuberositas  ulnce)  for  the  oblique  ligament. 

Its  outer  surface  is  the  lesser  sigmoid  cavity. 

Its  inner  surface  gives>  attachment  to  the  internal  lateral 
ligament,  and  the  flexor  digitorum  sublimis,  flexor  profundus 
digitorum,  and  one  head  of  pronator  radii  teres. 

Greater  sigmoid  cavity  (incisura  semilunaris)  is  a  large, 
semilunar  depression  between  the  olecranon  and  coronoid  proc- 
esses, divided  into  two  unequal  lateral  parts  by  an  elevated 
ridge.  It  is  continuous  on  the  outer  side  with  the  lesser  sig- 
moid cavity  and  articulates  with  the  trochlear  surface  of  the 
humerus. 


OSTEOLOGY. 


73 


tICTdJI    DICITORU 
1UBLIMII 


ccrnrioiutZ  orig. 


Styloid  freer u 

Stylotd£rct4St 

Fig.  49. 
Ulna  and  radius,   anterior  aspect. 


74  HUMAN    ANATOMY. 

Lesser  sigmoid  cavity  (incisura  radialis)  is  an  oval,  con- 
cave, articular  depression,  external  to  the  coronoid  process,  for 
articulation  with  the  head  of  the  radius.  Its  prominent  ex- 
tremities give  attachment  to  the  orbicular  ligament. 

The  lower  extremity  is  small  and  cylindrical  and  presents : — 

Head  (capitulum  ulnce),  an  external,  rounded,  articular 
process,  for  the  triangular  flbrocartilage  below  and  the  sigmoid 
cavity  of  the  radius  externally ; 

Styloid  process  {processus  styloideus)  projects  from  the 
posterior  and  internal  part  of  the  extremity,  its  apex  gives  at- 
tachment to  the  internal  lateral  ligament  of  the  wrist,  and  it  is 
marked  at  its  root  by  a  depression  between  it  and  the  head,  for 
attachment  of  the  fibrocartilage ; 

Groove,  upon  the  posterior  surface,  for  passage  of  extensor 
carpi  ulnaris. 

It  articulates  with  two  bones — humerus  and  radius. 

Its  muscular  attachments  are  sixteen — brachialis  anticus, 
triceps,  anconeus,  flexor  and  extensor  carpi  ulnaris,  pronator 
radii  teres,  flexor  sublimus  and  profundus  digitorum,  pronator 
quadratus,  supinator  breyis,  extensor  indicis,  extensor  ossis 
metacarpi,  extensor  secundi  internodii  pollicis  and  flexor  longus 
pollicis. 

Its  ossific  centers  are  three — one  each  for  shaft,  olecranon 
and  inferior  extremity. 

The  radius  is  a  long  bone,  shorter  than  the  ulna,  situated 
on  the  outer  side  of  the  forearm,  the  upper  end  small,  the  shaft 
slightly  curved,  and  the  lower  end  expanded  to  form  part  of  the 
wrist  joint.     It  consists  of  shaft,  upper  and  lower  extremity. 

The  shaft  (corpus  radii)  is  prismoid,  slightly  curved,  and 
presents 

An  internal  or  interosseous  border  (crista  interossea) , 
sharp  and  prominent,  for. interosseous  membrane; 

An  anterior  or  palmar  border  (mar go  volaris)  marked  at 
its  upper  third  by  an  oblique  line,  for  attachment  of  flexor 
longus  pollicis,  supinator  brevis  and  flexor  sublimis  digitorum; 

Anterior,  palmar,  or  flexor  surface  (fades  volaris),  affords 
attachment  above  for  flexor  longus  pollicis,  below  for  pronator 
quadratus,  and  presents  at  the  junction  of  middle  and  upper 
two-thirds  a  nutrient  foramen  directed  upward; 

Posterior,  dorsal,  or  extensor  surface  (fades  dorsalis)  gives 
attachment  at  upper  third  to  supinator  brevis,  and  at  middle 
third  to  extensors  of  thumb. 

The  upper  extremity  presents: — 


OSTEOLOGY. 


75 


ft*  1XT.  CAJIPI    IAD. 

l/T.CMH     KAO 
1ST.    tUUMM    MTtftN 


J|£: '.""« 


Bto.  50. 

Radius  and  ulna,   posterior  aspect. 


76  HUMAN   ANATOMY. 

Head  (capitulum  radii) — a  cup-like  cylindrical  cavity,  for 
articulation  with  capitellum  of  humerus,  and  on  its  side  an  ar- 
ticulating surface  for  lesser  sigmoid,  cavity  of  ulna  and  orbicular 
ligament,  which  nearly  surrounds  it; 

Neck  (collum  radii),  the  constricted  portion  below  the 
head; 

Bicipital  tuberosity  (tuberositas  radii),  below  and  to  inner 
side,  divided  by  a  vertical  line  into  a  rough  surface  posteriorly, 
for  attachment  of  biceps  tendon,  and  smooth  surface  anteriorly 
for  bursa. 

The  lower  extremity,  large,  expanded  and  quadrilateral 
presents : — 

Carpal  articular  surface  (fades  articularis  carpea),  smooth, 
concave,  triangular  depression  divided  by  an  anteroposterior 
ridge  into  an  outer  facet  for  scaphoid  bone  and  inner  for 
semilunar ; 

Sigmoid  cavity  (incisura  ulnaris),  a  shallow  concavity  at 
inner  side  of  carpal  end,  for  articulation  with  ulnar  head ; 

Styloid  process  (processus  styloideus),  projects  obliquely 
downward  from  the  external  surface,  for  attachment  by  its  apex 
to  external  lateral  ligament  of  wrist  joint,  and  by  its  base  to 
insertion  of  supinator  longus  muscle.  Its  outer  surface  is 
marked  by  two  grooves  for  extensors  of  thumb ; 

The  posterior  surface  of  the  lower  extremity  is  also  marked 
by  three  grooves  from  without  inward  for  the  following:  ext. 
carpi  radialis  longior  and  brevior  in  first,  ext.  secundi  internodii 
in  second,  and  ext.  indicis,  ext.  communis  digitorum,  and  ext. 
minimi  digiti  in  third  innermost.  This  surface  has  also  attach- 
ment of  posterior  ligament  of  wrist. 

It  articulates  with  four  bones — humerus,  ulna,  scaphoid 
and  semilunar. 

Its  muscular  attachments  are  nine — biceps,  supinator  longus 
and  brevis,  flexor  digitorum  sublimis,  flexor  longus  pollicis, 
pronator  quadratus,  extensor  ossis  metacarpi  pollicis,  ext.  primi 
internodii  pollicis  and  pronator  radii  teres. 

Its  ossific  centers  are  three — one  each  for  shaft  and  each 
extremity. 

The  Hand. — The  bones  of  the  hand  consist  of  eight  carpus, 
five  metacarpus,  and  fourteen  phalanges;  total,  twenty-seven 
bones. 

The  carpus  (ossa  carpi)  consist  of  eight  small  bones  ar- 
ranged in  two  rows — first,  or  proximal  row,  from  the  radial  side 
inward  are  scaphoid,  semilunar,  cuneiform  and  pisiform;  the 


OSTEOLOGY. 


77 


second,  or  distal  row,  in  same  order  are  trapezium,  trapezoid,  os 
magnum  and  unciform. 

Scaphoid  (os  naviculare  mantis — boat-shaped),  largest  of 
first  row,  convex  above,  concave  below,  articulates  with  five  bones, 


Phal, 


Cafpni 


taearpa* 


2* Aw 


?Jtem 


Fig.  51. 
Carpus,   metacarpus,    and   phalanges,   dorsal   surface. 

as  follows:  superior  surface,  with  radius;  inferior,  with 
trapeziuln  and  trapezoid;  internal,  with  semilunar  above  and  os 
magnum  beneath.  The  external  surface  has  attachment  of  ex- 
ternal lateral  ligament  of  wrist. 


78  HUMAN    ANATOMY. 

Semilunar  (os  hmatum — half-moon),  crescentic  in  out- 
line,  presents  articulating  surfaces  for  five  bones,  as  follows: 
superior  convex  surface  with  radius,  inferior  concave  facet  with 
os  magnum  and  unciform,  quadrilateral  internal  facet  with 
cuneiform,  and  external  with  scaphoid. 

Cuneiform  (os  triquetrum)  is  wedge-shaped,  the  base,  di- 
rected outward,  articulates  with  the  semilunar,  apex  with  the 
interarticular  fibrocartilage  of  wrist  joint,  inferior  surface  with 
unciform,  and  anterior  with  pisiform ;  in  all,  three  bones. 

Pisiform  (os  pisiforme — pea-like) is  a  small,  pea-shaped 
bone  articulating  with  anterior  surface  of  cuneiform,  and  afford- 
ing attachment  to  annular  ligament  and  two  muscles,  flexor 
carpi  ulnaris,  abductor  minimi  digiti. 

Trapezium  (os  muXtangulum — a  table),  a  very  irregular 
bone,  articulates  above  by  concave  surface  with  scaphoid ;  below, 
by  surface  concave  from  side  to  side,  convex  from  before  back- 
ward, with  first  metacarpal ;  by  internal  surface  with  trapezoid, 
inferior  with  second  metacarpal.  Its  dorsal  surface  is  rough; 
its  palmar  grooved  by  flexor  carpi  radialis  tendon.  Muscular 
attachments  are  three — flexor  ossis  metacarpi,  flexor  brevis  pol- 
licis  and  abductor  pollicis. 

Trapezoid  (os  multangulum  minus),  smallest  of  second 
row,  is  wedge-shaped,  apex  palmar ;  articulates  with  four  bones — 
superior  surface  with  scaphoid,  inferior  with  second  metacarpal, 
external  with  trapezium,  internal  with  os  magnum  and  inter- 
osseous ligament. 

It  has  one  muscular  attachment  for  flexor  brevis  pollicis. 

Os  magnum,  or  capitate  (os  capitatum),  the  largest  car- 
pal bone,  consists  of  a  body,  neck,  and  head.  The  latter  projects 
from  the  superior  surface  and  articulates  with  the  scaphoid  and 
semilunar.  The  inferior  surface  articulates  with  second,  third, 
and  fourth  metacarpal  bones;  the  external  with  trapezoid,  and 
internal  with  unciform;  in  all  seven  bones. 

Muscular  attachment  for  flexor  brevis  pollicis. 

Unciform  (os  hamatum — hook-like),  a  wedge-shaped 
bone,  so  named  from  the  hook-like  process  (hamulus  ossis 
hamati)  projecting  from  its  anterior  surface,  below  its' "articu- 
lation with  fourth  and  fifth  metacarpals,  and  above  its  articula- 
tion with  semilunar.  This  process  gives  attachment  to  annular 
ligament,  flexor  brevis  minimi  digiti,  flexor  ossis  metacarpi 
minimi  digiti,  and  is  grooved  for  passage  of  other  flexor  ten- 
dons. External  surface  articulates  with  os  magnum  and  inter- 
nal with  cuneiform. 


OSTEOLOGY. 


79 


Muscular  attachments  are  those  to  unciform  process.     Each 
carpal  bone  is  developed  from  a  single  ossific  center. 


Fig.  52. 
Carpus,  metacarpus,   and  phalanges,  palmar  surface. 

Table  of  Articulations  of  Carpal  Bones. — Scaphoid;  5; 
semilunar,  5  ;  cuneiform,  3  ;  pisiform,  I  ;  trapezium,  I  ;  trapezoid, 
I ;  oa  magnum,  ',  ;  unciform,  5. 


80  HUMAN    ANATOMY. 

The  metacaepus  (ossa  metacarpalia)  are  five  long  bones, 
resembling  each  other,  and  presenting  a  shaft  (corpus)  and  two 
extremities.  Anterior  surface  is  concave,  posterior  convex; 
superior,  carpal  or  proximal  extremity  or  base  (basis),  irregular 
for  articulation  with  carpal  bones  and  with  the  adjoining  bones; 
inferior,  digital  or  distal  extremity  or  head  (capitulum) ,  pre- 
sents rounded  head  for  articulation  with  phalanges.  The  first 
metacarpal  (os  metacarpale  I),  for  thumb  is  supported  on 
trapezium,  articulates  with  first  phalanx,  and  has  four  muscles 
attached— first  dorsal  interosseus,  flexor,  and  extensor  ossis 
metacarpi  pollicis  and  the  flexor  brevis  pollicis;  the  second 
metacarpal  (os  metacarpale  II)  by  three,  trapezium,  trapezoid 
and  os  magnum,  articulates  also  with  third  metacarpal  and 
second  phalanx,  and  has  six  muscles  attached — first  and  second 
dorsal  interosseus,  first  palmar  interosseus,.  flexor  carpi  radialis, 
and  extensor  carpi  radialis  longior  and  the  adductor  obliquus 
pollicis;  the  third  metacarpal  (os  metacarpale  III)  supported  by 
os  magnum,  articulates  also  with  second  and  fourth  metacarpal 
and  third  phalanx,  and  has  six  muscles  attached — flexor  carpi 
radialis,  adductor  obliquus  pollicis,  extensor  carpi  radialis 
brevior,  adductor  pollicis,  and  second  and  third  dorsal  inter- 
osseus. The  fourth  metacarpal  (os  metacarpale  IV)  is  supported 
on  os  magnum  and  unciform,  articulated  with  third  and  fifth 
metacarpal  and  fourth  phalanx,  and  has  three  muscles  attached — 
second  palmar  and  third  and  fourth  dorsal  interosseus.  The 
fifth  metacarpal  (os  metacarpale  V)  supported  on  unciform, 
articulates  with  fourth  metacarpal  and  fifth  phalanx,  and  has 
five  muscles  attached — flexor  ossis  metacarpi  minimi  digiti, 
flexor  and  extensor  carpi  ulnaris,  and  fourth  dorsal  and  third 
palmar  interosseus. 

Ossific  centers  are  two  for  each  bone,  one  each  for  shaft 
and  head,  except  thumb,  which  has  one  each  for  shaft  and 
base,  resembling  the  phalanges. 

Phalanges  of  the  Hand  (phalanges  digitorum  manus). 
— Each  finger  has  three  phalanges  (intemodia),  except  the 
thumb,  which  has  but  two.  Palmar  surface  concave,  dorsal  con- 
vex; the  superior  extremity  articulates  with  head  of  metacarpal, 
and  the  inferior,  concave  from  side  to  side,  convex  from  before 
backward,  articulates  with  second  phalanx,  which  presents  an 
opposite  arrangement,  except  in  the  thumb,  where  it  articulates 
with  ungual  or  terminal  phalanx. 

[Phalanges  as  a  generic  term  is  translated,  intemodia; 
when  applied  to  the  phalanges  of  the  hand,  phalanges  digitorum 


OSTEOLOGY.  81 

manus,  in  contradistinction  to  the  phalanges  of  the  foot,  pha- 
langes digitorum  pedis.] 

The  second  phalangeal  articulation  is  the  same,  and  the 
ungual  phalanx  presents  a  rough,  arrow-shaped  extremity. 

The  muscular  insertions  to  the  first  row  are :  to  thumb  four, 
flexor  brevis,  abductor  and  adductor  pollicis,  and  extensor  primi 
internodii;  to  index  two,  first  palmar  and  dorsal  interosseus;  to 
middle  two,  second  and  third  dorsal  interossei;  to  ring,  two, 
second  palmar  and  fourth  dorsal  interosseus;  to  little  three, 
flexor  brevis  and  abductor  minimi  digiti  and  third  palmar  inter- 
osseus. 

The  insertions  to  second  row  are:  extensor  secundi  inter- 
nodii and  flexor  longus  pollicis;  and  to  each  of  the  others  four, 
extensor  communis  digitorum,  flexor  sublimis  digitorum,  with 
the  addition  of  extensor  indicis  to  index  and  extensor  minimi 
digiti  to  little. 

The  insertions  to  third  row  are:  extensor  communis  digi- 
torum and  flexor  profundus. 

Ossific  centers  are  two  for  each  bone,  one  each  for  shaft 
and  base. 

THE   LOWER    EXTREMITY. 

The  lower  extremity  consists  of  the  thigh,  leg,  and  foot.  It 
is  connected  to  the  trunk  by  the  pelvic  girdle  formed  by  the  hip 
bones  and  sacrum,  and  contains  the  following  bones :  os  innom- 
inatum,  femur,  patella,  tibia,  fibula,  seven  tarsus,  five  meta- 
tarsus and  fourteen  phalanges. 

The  os  inxominatum,  or  hip  bone,  is  a  large,  irregular 
bone  forming  the  lateral  and  anterior  walls  of  the  pelvis,  and 
consisting  of  three  bones,  ilium,  ischium  and  pubes,  united 
about  puberty.    It  presents 

The  acetabulum  or  cotyloid  cavity,  a  deep,  cup-shaped  cav- 
ity, for  articulation  of  the  head  of  the  femur — the  ischium 
forming  a  little  more  than  two-fifths,  the  ilium  a  little  less  than 
two-fifths,  and  the  pubes  one-fifth.  The  bottom  of  the  cavity 
presents  a  circular  depression  (fossa  acetabuH),  lodging  a  mass 
of  Eat,  and  giving  attachment  by  its  edges  to  the  ligamentum 
teres,  and  continuous  below  with  a  deep  notch,  the  cotyloid 
aotch  {inciswra  acetabidi),  for  attachment  of  cotyloid  and  part 
of  Ligamentum  teres,  converted  into  a  foramen  by  the  trans- 
verse ligament  for  (he  entrance  of  the  nutrient  vessels  and 
nerves.  The  margin  of  the  acetabulum  is  deepened  by  a.  fibro- 
cartilaginous  ring. 

The  obturator,  or  thyroid,  foramen  (foramen  obiuratvm)  is 


82 


HUMAN    ANATOMY. 


an  aperture  large  and  ovoidal  in  the  male,  small  and  triangular 
in  the  female,  situated  on  the  anterior  inferior  surface  between 
the  ischium  and  pubes.  It  is  closed,  in  the  recent  state,  by  a 
strong  membrane  attached  to  its  margins  except  above  exter- 
nally, where,  a  foramen  exists  for  obturator  vessels  and  nerve. 


OESCLUII    WffUUBI 


Fig.  53. 
Os  innominatum,   outer  surface. 


The  ilium  (os  ilium),  broad,  flat,  and  triangular,  forms 
the  greater  part  of  the  bone,  its  base  above,  its  apex  at  the 
acetabulum. 

The  external  surface,  or  dorsum,  concave  in  front  and  be- 
hind, presents  from  below  upward 


OSTEOLOGY.  y;{ 

A  groove,  just  above  the  acetabulum,  for  the  reflected  ten- 
don of  the  rectus  femoris  muscle; 

The  inferior  curved  line,  or  inferior  "luteal  line  (linea 
glutecB  inferior),  marking  the  lower  border  of  the  gluteus 
minimus  ; 

The    middle   curved   line,   or   anterior  gluteal   line    (linea 


Fig.  54. 
Os   innominatum,    inner   surface. 


glutem  anterior),  the  longest  of  the  three,  marking  the  lower 
border  of  the  gluteus  medius ;  and 

The  superior  curved  line,  or  posterior  gluteal  line  (linea 
glutecB  posterior),  the  shortest,  marks  the  lower  anterior  border 
of  the  glutens  maximus.  and  from  the  Burface  below  which 
a  i  ise  a  few  fibers  of  the  pyriformis. 

The  upper  expanded   border  forms  the-  cresl  of  the   ilium 

ta  Uiaca  \ ,  terminal  ing  in  fronl  in 


§4  HUMAN    ANATOMY. 

The  anterior  superior  spinous  process  {spina  iliaca  anterior 
superior);,  giving  origin  to  the  sartorius  and  tensor  vaginas 
femoris  muscles  and  Poupart's  ligament,  below  which  is 

The  anterior  inferior  spinous  process  (spina  iliaca  anterior 
inferior),  for  the  iliofemoral  ligament,  and  the  straight  tendon 
of  the  rectus  femoris  muscle;  and  behind  in 

The  posterior  superior  spinous  process  (spina  iliaca  pos- 
terior superior),  for  the  oblique  band  of  the  sacroiliac  ligament, 
and  part  of  the  multifidus  spina?  muscle,  below  which  is 

The  posterior  inferior  spinous  process  (spina  iliaca  pos- 
terior inferior) ,  for  attachment  of  the  great  sacrosciatic  ligament. 

Between  the  superior  and  inferior  spinous  processes,  both 
anteriorly  and  posteriorly,  is  a  notch,  the  former  for  partial  at- 
tachment of  the  sartorius  and  passage  of  the  external  cutaneous 
nerve. 

The  internal  concave  surface,  or  venter,  presents 

The  internal  iliac  fossa  (fossa  iliaca),  lodging  the  iliacus 
muscle,  and  having  a  nutrient  foramen  at  its  lower  part; 

Iliopectineal  line  (linea  arcuata),  limiting  the  fossa  below, 
and  separating  the  false  from  the  true  pelvis; 

Rough  surface,  divided  into  two  parts — the  posterior  por- 
tion (tuberositas  iliaca),  for  posterior  sarcoiliac  ligaments,  and 
lower  auricular  or  anterior  surface  (fades  auricularis)  for  ar- 
ticulation with  sacrum. 

The  ischium  (os  ischii)  forms  the  outer  back  part  of  pel- 
vis, and  consists  of  a  body,  tuberosity,  and  ascending  ramus. 

The  external  surface  of  the  body  forms  a  little  more  than 
two-fifths  of  the  acetabulum,  and  presents 

A  groove  (sulcus  obturatorius)  below,  for  the  tendon  of 
the  obturator  externus. 

The  internal  surface  is  concave  and  smooth,  and  forms  the 
lateral  wall  of  the  true  pelvis. 

The  posterior  border  presents 

The  spine  (spina  ischiadica)  of  the  ischium^  projecting 
downward,  backward,  and  inward,  from  below  the  center  for 
attachment  of  the  gemellus  superior,  coccygeus,  and  levator  ani 
muscles,  and  lesser  sacrosciatic  ligament; 

Great  sacrosciatic  notch  (incisura  ischiadica  major),  a  deep 
notch  above  the  spine  converted  into  a  foramen  (foramen 
ischiadicum  majus),  by  the  lesser  sacrosciatic  ligament,  trans- 
mitting the  pyriformis  muscle,  superior  gluteal  nerve,  gluteal 
vessels,  sciatic  vessels  and  nerves,  and  the  internal  pudic  vessels 
and  nerves ; 


OSTEOLOGY.  85 

Lesser  sacrosciatic  notch  (incisura  ischiadica  minor),  be- 
low the  spine,  and  between  it  and  the  tuberosity,  converted  into 
a  foramen  (foramen  ischiadicum  minus)  by  the  great  sacro- 
sciatic ligament,  transmitting  the  obturator  internus  muscle  and 
nerve,  the  internal  pudic  vessels  and  nerves.  The  lowest  por- 
tion of  the  body  presents 

Tuberosity  (tuber  ischiadicum),  with 

Outer  lip,  for  attachment  of  part  of  adductor  magnus  and 
quadriceps  f emoris ; 

Inner  tip,  for  part  of  great  sacrosciatic  ligament,  erector 
penis,  and  transversus  perinaei; 

Groove,  on  inner  lip,  for  internal  pudic  vessels  and  nerve; 

Intermediate  surface,  for  semimembranosus,  semitendino- 
sus,  biceps,  adductor  magnus,  gemellus  inferior  and  great  sacro- 
sciatic ligament. 

The  ascending  or  inferior  ramus  (ramus  inferior  ossis 
ischii)  passes  upward  and  inward  from  the  tuberosity  to  join 
the  descending  ramus  of  the  pubes,  forming  part  of  the  inner 
margin  of  the  obturator  foramen.  It  gives  attachment  to 
gracilis,  obturator  externus,  part  of  adductor  magnus,  erector 
penis  and  transversus  perinaei; 

The  pubes  (os  pubis)  forms  the  anterior  part  of  the  pelvis 
and  consists  of  a  body,  horizontal  ramus,  and  descending  ramus. 

The  body  (corpus  ossis  pubis)  is  quadrilateral,  and  presents 

An  anterior  surface,  for  attachment  of  adductor  longus  and 
brevis,  and  part  of  gracilis,  adductor  magnus  and  obturator  ex- 
ternus ; 

Posterior  surface,  forming  anterior  wall  of  true  pelvis  and 
giving  attachment  to  levator  ani  and  part  of  obturator  internus ; 

Spine  (tuberculum  pubicum) ,  upon  the  upper  border,  for 
Poupart's  ligament  and  outer  pillar  of  external  abdominal  ring; 

Iliopectineal  line  (linea  arcuata),  continuous  with  that  on 
ilium ; 

Crest,  along  the  upper  border,  internal  to  the  spine; 

Angle,  at  the  junction  of  the  inner  border  with  the  crest 
and  giving  attachment  to  internal  pillar  of  external  ring; 

Symphysis,  the  internal  oval  border  roughened  by  several 
ridges  for  articulation  with  opposite  bone. 

The  ascending  or  superior  ramus  (ramus  superior  ossis 
pubis)  joins  t lie  ilium,  forming  the  upper  part  of  the  obturator 
foramen,  ami  presents  at  its  lower  border  a 

Qroove,  for  the  obturator  vessels  and  nerve. 

The  descending  or   Inferior   ramus    (ramus  inferior  ossis 


gg  HUMAN    ANATOMY. 

pubis)   is  flat  and  thin,  and  joins  the  ascending  ramus  of  the 
ischium. 

Each  innominate  bone  articulates  with  three  bones — the  sa- 
crum, femur,  and  its  fellow  of  the  opposite  side. 

Its  muscular  attachments  are  thirty-three — [ilium],  latissi- 
mus  dorsi,  tensor  vaginas  femoris,  obliquus  externus,  erector 
spinas,  transversalis,  quadratus  lumborum,  gluteus  minimus, 
medius,  and  maximus,  rectus,  piriformis,  iliacus,  multifidus 
spinas,  sartorius — [ischium],  obturator  externus  and  intern  us, 
gemellus  superior,  coccj^geus,  levator  ani,  semimembranosus  and 
semitendinosus,  biceps,  quadratus  femoris,  adductor  magnus, 
gemellus  inferior,  erector  penis  and  transversus  perinasi — ■ 
[pubes],  pyramidalis,  obliquus  internus  and  externus,  psoas  par- 
vus, pectineus,  adductor  longus  and  brevis,  gracilis  and  com- 
pressor urethras. 

Its  ossific  centers  are  eight — one  primary  for  each  division 
and  five  epiphyses,  one  each  for  crest  of  ilium,  symphysis,  tuber- 
osity of  ischium,  anterior  spinous  process,  and  acetabulum. 

The  femur,  or  thigh  bone,  is  the  largest,  longest  and 
strongest  bone  in  the  body.  In  the  erect  position  it  inclines 
toward  its  fellow  at  the  knee,  being  widely  separated  above, 
forming  the  sides  of  a  triangle,  the  base  of  which  isi  greater  in 
females  from  the  greater  breadth  of  the  pelvis.  It  consists  of 
a  shaft,  an  upper  and  lower  extremity. 

The  shaft  (corpus  femoris)  expanded  above  and  below, 
curved  and  twisted,  convex  in  front,  concave  behind,  is  nearly, 
cylindrical  throughout,  and  presents 

Smooth  anterior  surface,  for  origin  of  crureus  and  sub- 
crureus  muscles; 

Lateral  surfaces,  covered  by  the  vasti  externus  and  internus ; 

The  posterior  surface,  rough  and  prominent,  has  its 

Nutrient  foramen  between  the  middle  and  lower  two-thirds 
directed  upward; 

Linea  aspera,  a  rough,  prominent,  longitudinal  crest  de- 
scending from  the  trochanters  along  the  middle  third,  bifur- 
cating and  diverging  at  the  inferior  extremity  to  the  condyles, 
inclosing 

The  popliteal  space  (planum  popliteum) ,  a  smooth,  trian- 
gular space,  on  which  rests  the  popliteal  artery,  and  which  is 

Grooved  at  its  inner  margin  by  the  femoral  artery. 

The  outer  (labium  laterale)  and  inner  (labium  mediate) 
lip  of  the  linea  aspera  give  attachment  to  the  vasti  externi  and 
interni,  three  adductors,  pectineus,  biceps  and  gluteus  maximus. 

The  upper  extremity  presents  the  following: — 


OSTKOLOOY. 


87 


ifirUud^ 


Fio.  66. 

The  femur,  anterior 
surface. 


Fig.  56. 

The  femur,  posterior 
surface. 


gg  HUMAN    ANATOMY. 

The  head  {caput  femoris),  forming  two-fifths  of  a  sphere, 
articulates  with  the  acetabulum,  having  a  central  oval  depression 
(fovea  capitis  femoris)  for  the  ligamentum  teres; 

Neck  (collum  femoris),  pyramidal,  with  excavated  surfaces, 
connects  the  head  with  the  shaft,  the  angle  of  its  obliquity  to  the 
shaft  varying  much  from  puberty  to  old  age,  being,  in  the  adult, 
about  130  degrees; 

The  great  trochanter  (trochanter  major),  a  large,  rough, 
quadrilateral  eminence,  directed  upward,  outward,  and  back- 
ward, its  external  surface  marked  by  a  diagonal  line  for  inser- 
tion of  gluteus  medius  tendon,  its  outer  surface  smooth  for  the 
passage  of  the  gluteus  maximus  tendon,  separated  by  a  bursa, 
and  its  superior  surface  marked  by  three  impressions,  from  be- 
hind forward,  for  pyriformis,  obturator  internus  and  gemelli 
muscles.  The  gluteus  minimus  is  attached  to  the  anterior 
border ; 

Digital  or  trochanteric  fossa  (fossa  trochanterics),  to  the 
inner  side  of  the  great  trochanter,  for  insertion  of  obturator 
externus  tendon; 

The  lesser  trochanter  (trochanter  minor),  a  small,  conical 
projection  at  the  base  of  the  neck  posteriorly,  and  giving  attach- 
ment to  the  tendon  of  psoas  magnus  muscle,  the  iliacus  being 
inserted  below; 

Anterior  intertrochanteric  line  (linea  intertro chant erica) 
connects  the  trochanters  in  front  and  gives  attachment  at  its 
upper  part  to  the  capsular  ligament; 

Posterior  intertrochanteric  line  (crista  intertro chanterica) , 
a  much  more  prominent  ridge,  connects  them  behind ; 

Tubercle  of  the  femur,  a  prominence  at  the  junction  of  the 
neck  with  the  great  trochanter,  is  the  meeting-place  of  five  mus- 
cles— two  gemelli,  obturator  internus,  gluteus,  minimus  and 
vastus  externus; 

Tubercle  of  the  quadratus,  about  the  center  of  the  posterior 
intertrochanter  line,  for  the  quadratus  femoris; 

Linea  quadrati,  passes  vertically  downward  from  the  mid- 
dle of  the  posterior  line,  and  gives  attachment  to  part  of 
adductor  magnus  and  quadratus  femoris. 

The  inferior  extremity,  large  and  cuboidal  in  form,  pre- 
sents : — 

External  condyle  (condylus  lateralis),  shorter  and  broader 
than  the  internal,  has  behind  its  center  the  outer  tuberosity  for 
the  external  lateral  ligaments  of  the  knee,  and  a  groove  below 
the  tuberosity  for  the  tendon  of  the  popliteus  muscle.     It  also 


OSTEOLOGY.  89 

gives  origin  to  the  outer  head  of  the  gastrocnemius,  above  which 
arises  the  plantaris  muscle ; 

The  internal  condyle  (condylus  medialis),  longer  by  half 
an  inch  and  more  prominent  (so  as  to  bring  them  on  the  same 
horizontal  plane  owing  to  the  obliquity  of  the  shaft),  has  on 
the  inner  surface  the  inner  tuberosity  for  the  internal  lateral 
ligament; 

Adductor  tubercle,  at  the  summit  of  the  internal  condyle, 
marks  the  termination  of  the  inner  ridge  of  the  linea  aspera,  and 
gives  attachment  to  tendon  of  adductor  magnus; 

Depression,  above  the  articular  surface  of  the  internal  con- 
dyle posteriorly,  for  the  origin  of  the  inner  head  of  gastrocne- 
mius; 

Intercondyloid  notch  (fossa  intercondyloidca) ,  separates 
the  condyles  behind,  and  lodges  the  crucial  ligaments; 

Trochlear  (fades  patellaris)  is  a  smooth  surface  between 
the  condyles  in  front  and  articulates  with  the  patella  in  front. 
The  inferior  surfaces  of  both  condyles  are  smooth,  continuous 
in  front,  covered  with  cartilage  in  the  recent  state,  for  articula- 
tion with  the  head  of  the  tibia.  The  femur  articulates  with 
three  bones — innominatum,  tibia  and  patella. 

Its  muscular  attachments  are  twenty-three  (23) — two  vasti, 
three  adductors,  gluteus  maximus,  medius  and  minimus,  pyri- 
formis,  obturator  externus  and  interims,  two  gemelli,  quadratus 
femoris,  psoas  magnus,  iliacus,  biceps,  pectineus,  crureus,  sub- 
crureus,  gastrocnemius,  plantaris  and  popliteal. 

its  ossific  centers  are  five — three  primary,  one  each  for 
shaft  and  each  extremity,  and  one  epiphysis  for  each  trochanter. 

The  patella  is  a  flat,  triangular  bone,  sesamoid  in  origin, 
developed  in  the  tendon  of  the  ^quadriceps  extensor,  forming  the 
knee-cap,  and  entering  into  the  formation  of  the  knee-joint. 

The  convex  anterior  surface  is  roughened  by  apertures  for 
nutrient  vessels. 

The  posterior  or  internal  surface  (fades  articularis)  is 
divided  by  a  vertical  and  transverse  ridge  into  three  surfaces — 
two  smooth,  articular  facets  for  either  condyle  of  femur  above, 
the  outer  being  deeper  and  broader,  and  a  rough  surface  below, 
the  apex  (apex  pateUce)  for  ligamentum  patellae. 

The  superior  border  (basis  patella')  gives  attachment  to  the 
rectus  and  CTureus  muscles,  tbe  internal  and  external  lateral  bor- 
ders to  the  vasti  internus  and  externus. 

It  articulates  with  the  femur. 

[ta  muscular  attachments  are  four  muscles — rectus  Eemoris, 
crureus,  vastus  externus  and  vastus  internus. 


90  '  HUMAN    ANATOMY. 

It  is  developed  from  a  single  ossific  center. 

The  tibia,  or  shin  bone,  extends  on  the  internal  aspect  of 
the  leg  from  the  knee  to  ankle,  and  consists  of  a  shaft,  upper  and 
lower  extremity. 

The  shaft  (corpus  tibia?)  is  triangular,  prismoid,  with  the 
base  above. 

Its  anterior  border  and  internal  surface  are  subcutaneous, 
the  former  forming  the  shin  or  crest  of  the  tibia  (crista 
anterior) . 

The  posterior  surface  (fades  posterior)  presents  above  an 
oblique  line  (linea  popiitea)  for  the  lower  border  of  the  pop- 
liteal muscle  and  fascia,  and  origin  of  the  soleus,  and  parts  of 
flexor  longus  digitorum  and  tibialis  posticus  muscles. 

It  presents  just  below  the  oblique  line  a  nutrient  canal 
(foramen  nutricium),  the  largest  in  the  skeleton,  directed 
downward. 

Its  external  border,  or  interosseous  ridge  (crista  interossea) 
is  thin,  for  attachment  of  interosseous  membrane. 

The  external  surface  and  internal  borders  are  covered  by 
muscles. 

The  superior  expanded  surface  presents: — 

Head,  consisting  of  two  tuberosities,  internal  and  external 
(condylus  medialis  and  condylus  lateralis),  each  having  upon 
their  upper  surfaces  a  smooth,  concave,  ovoidal  articulating  facet 
(fades  articularis  superior)  for  the  condyles  of  the  femur, 
separated  by 

The  spinous  process  (eminentia  intercondyloidea)  of  the 
tibia,  in  front  and  behind  which  is  impression  for  crucial  liga- 
ments, and  laterally  tubercles  for  the  extremities  of  the  semi- 
lunar cartilages; 

Tubercle  (tuberositas  tibial),  on  the  anterior  surface  of  the 
head,  between  the  tuberosities,  for  the  insertion  of  ligamentum 
patellae ; 

Popliteal  notch  (incisura  popiitea),  separating  the  tuber- 
osities posteriorly,  for  attachment  of  the  posterior  crucial 
ligament ; 

Transverse  groove,  on  the  posterior  surface  of  the  inner 
tuberosity,  for  insertion  of  semimembranosus  tendon; 

Facet  (fades  articularis  fibularis),  upon  the  posterior  sur- 
face of  the  outer  tuberosity,  for  articulation  of  the  head  of  the 
fibula. 

The  inferior  extremity,  smaller  than  the  superior,  is  quadri- 
lateral, and  presents  in  front  a  smooth  surface  for  extensor  ten- 
dons ;  behind,  a  groove  for  flexor  longus  pollicis  tendon ;  exter- 


OSTEOLOGY. 


91 


jtfro* 


■^''"/^H. 


TrtTTB 


I  H'U.~.t 


Fig.  57. 

The  tibia  and   fibula,  anterior 
surface. 


'tyUiSfmem 


FIG.    58. 

The  tibia  and  fibula,  posterior 
surface. 


92  HUMAN    ANATOMY, 

nally,  a  rough,  triangular,  articular  surface,  for  fibula,  and  in- 
ternally 

The  internal  malleolus  (malleolus  medialis),  which  projects 
downward,  and  articulates  by  its  outer  surface  with  the  as- 
tragalus. 

Its  inner  surface  is  smooth  and  subcutaneous;  its  posterior 
border  is  grooved  (sulcus  malleolaris)  for  the  tendons  of  the 
tibialis  posticus  and  flexor  longus  digitorum  muscles,  and  to  its 
tip  is  attached  the  internal  lateral  ligament. 

It  articulates  with  three  bones — femur,  fibula  and  as- 
tragalus. 

Its  muscular  attachments  are  twelve — ligamentum  patellae, 
popliteus,  soleus,  flexor  longus  digitorum,  tibialis  posticus,  semi- 
membranosus and  tendinosus,  gracilis,  sartorius,  tibialis  anticus, 
extensor  longus  digitorum  and  biceps. 

It  is  developed  from  three  ossific  centers,  one  each  for  shaft, 
upper  and  lower  extremities. 

The  fibula,  peroneal,  or  calf-bone,  is  a  long,  slender  bone 
on  the  outer  aspect  of  the  leg,  and  consists  of  a  shaft,  upper  and 
lower  extremity. 

The  shaft  (corpus  fibulce)  is  prismoidal,  four-sided,  twisted 
on  itself,  and  arched  backward.  Its  antero-internal  border,  or 
interosseous  ridge  (crista  interossea),  gives  attachment  to  the 
interosseous  membrane.  The  postero-internal  border  (crista 
medialis),  called  also  oblique  line,  and  the  other  surface  and 
borders  give  attachment  to  all  the  muscles  except  the  biceps. 

Nutrient  foramen,  about  the  middle  of  the  anterior-internal 
surface,  is  directed  downward. 

The  superior  extremity  presents  a  neck,  supporting  a 
rounded,  irregular  head  (capitulum  fibula),  which  articulates 
by  a  flattened  facet  on  its  inner  surface  with  the  tibia,  and  is 
prolonged  upward  on  its  outer  side  by  the  styloid  process  (apex 
capituli  fibula),  giving  attachment  to  the  biceps  tendon  and  the 
external  lateral  ligament  of  the  knee. 

The  inferior  extremity  expands  into  the  external  malleolus 
(malleolus  lateralis),  with  its  convex  internal  surface  for  ar- 
ticulation with  astragalus,  outer  convex  surface  subcutaneous, 
and  posterior  border  deeply  grooved  (sulcus  malleolaris)  for 
tendons  of  peroneus  longus  and  brevis  muscles. 

To  the  summit  is  attached  the  middle  fasiculus  of  the  ex- 
ternal lateral  ligament,  and  to  rough  depressions  in  front  and 
behind  the  anterior  and  posterior  fasciculi. 

It  articulates  with  two  bones,  tibia  and  astragalus. 


OSTEOLOGY.  93 

Its  muscular  attachments  are  nine :  soleus,  biceps,  three 
peronei,  tibialis  posticus,  flexor  longus  ballucis,  extensor  longus 
digitorum  and  extensor  longus  hallucis. 

It  is  developed  from  three  ossific  centers,  one  each  for  shaft, 
head  and  malleolus. 

THE  FOOT. 

The  bones  of  the  foot  consist  of  seven  tarsus,  five  metatar- 
sus, and  fourteen  phalanges. 

The  tarsal  bones  (ossa  tarsi)  are:  calcaneum,  astragalus, 
cuboid,  scaphoid,  and  internal,  middle,  and  external  cuneiform. 

They  may  be  arranged  into  two  series,  anterior  and  poste- 
rior; the  calcis  and  astragalus  behind,  and  all  the  others  in 
front  of  the  calcaneocuboid  and  astragaloscaphoid  joints  [Cho- 
part's]. 

Calcaneum,  or  os  calcis,  the  largest,  is  irregularly  cuboidal. 

The  superior  surface  presents  two  articular  surfaces  for 
the  astragalus,  separated  by  a  groove  for  the  calcaneoastragaloid 
ligament,  and  internally  a  projecting  process,  the  sustentaculum 
tali,  fur  calcaneocuboid  ligament.  The  inferior  surface,  rough 
and  excavated,  presents  two  tubercles,  an  outer  and  inner 
tubercle,  for  muscles  and  ligaments. 

Internal  surface  is  concave,  for  passage  of  flexor  longus 
and  tibialis  posticus  tendons,  and  plantar  vessels  and  nerves. 

External  surface  presents  tubercle  {processus  trocldearis) 
for  external  lateral  ligament  of  ankle  and  grooves  for  peroneal 
tendons. 

Posterior  surface,  projecting  behind  {tuber  calcanei),  pre- 
sents a  smooth  surface  above  for  bursa  and  rough  below  for 
attachment  of  tendo  Achillis. 

It  articulates  with  astragalus  and  cuboid. 

Muscular  attachments  are  eight:  tendo  Achillis,  plantaris, 
tibialis  posticus,  abductor  hallucis,  a.  minimi  digiti,  flexor  brevis 
digitorum,  accessorius  and  extensor  brevis  digitorum. 

Astragalus  (tales)  is  an  irregular,  short  bone,  consisting 
of  body  (corpus  tali),  neck  (collum  tali),  and  head  (caput  tali). 
The  quadrilateral  body  presents  four  articular  surfaces,  above 
for  lower  extremity  of  tibia  and  internal  malleolus  and  external 
malleolus;  below,  two  surfaces  for  os  calcis,  separated  by  deep 
groove  for  interosseous  calcaneoastragaloid  ligament;  posteriorly 
it  presents  a  deep  groove  (sulcus  m.  flexor  hallucis  longi)  for 
flexor  Longue  ballucis  tendon;  and  anteriorly,  the  rounded  con- 
vex head  supported  on  neck  articulates  with  scaphoid,  and  rests 
upon  calcaneoscaphoid  ligament. 


94  HUMAN    ANATOMY. 

It  articulates  with  four  bones :  tibia,  fibula,  scaphoid  and 
os.  calcis.     It  has  no  muscular  attachments. 

Cuboid  (os  cuboideum—cuhe-like)  is  a  small,  pyramidal 
bone,  between  the  os  calcis  and  the  fourth  and  fifth  metatarsal 
bones  on  the  outer  side  of  the  foot.  * 

The  upper  or  dorsal  surface  is  rough  for  ligamentous  at- 
tachment; the  lower  or  plantar  surface  is  grooved  (sulcus  m. 
peronwi  longi)  for  tendon  of  peroneus  longus,  behind  which  is 
a  ridge  for  the  long  calcaneocuboid  ligament,  terminating  ex- 
ternally in  the  tuberosity  of  the  cuboid  (tuberositas  ossis 
cuboidei). 

The  external  surface  has  a  deep  notch,  the  outer  extremity 
of  the  peroneal  groove. 

The  posterior  surface  has  triangular  facet  for  os  calcis,  the 
anterior  has  two  facets,  separated  by  a  ridge  for  the  fourth  and 
fifth  metatarsals,  and  the  internal  surface  has  broad,  square 
facet  for  external  cuneiform,  and  sometimes  a  smaller  facet  for 
scaphoid. 

It  articulates  with  four  and  occasionally  with  five  bones. 

It  has  one  muscular  attachment — part  of  flexor  brevis  pol- 
licis. 

Scaphoid,  or  navicular  bone  (os  naviculare  pedis),  is  a 
boat-like  bone  placed  between  astragalus  and  three  cuneiform 
bones. 

Its  posterior  concave  surface  articulates  with  head  of  as- 
tragalus, its  anterior  convex  surface  has  three  facets  for  cunei- 
form bones;  its  internal  border  presents  the  tuberosity  of  the 
scaphoid  (tuberosit as  ossis  navicularis)  for  insertion  of  tibialis 
posticus,  the  only  muscular  attachment.  Its  other  borders  are 
roughened  for  ligamentous  attachment. 

It  articulates  with  four  bones :  astragalus  and  three  cunei- 
forms. 

The  cuneiform  bones  are  named  from  their  position  the 
internal,  middle  and  external. 

The  internal  cuneiform  (os  cuneiforme  primum),  the 
largest,  has  its  base  below,  and  articulates  anteriorly  with  first 
metatarsal,  posteriorly  with  scaphoid,  and  externally  with 
second  metatarsal  and  middle  cuneiform.  The  plantar  surface 
presents  tuberosity  for  insertion  of  part  of  tibialis  posticus  and 
anticus  tendons,  the  only  muscular  attachments.  It  articulates 
with  four  bones:  scaphoid,  middle  cuneiform,  first  and  second 
metatarsals. 

The  middle  cuneiform  (os  cuneiforme  secundum),  the 
smallest,  has  its  base  upward,  and  articulates  posteriorly  with 


OSTEOLOGY. 


95 


Tn„trmas$   UruL,n  tf- 
S\%  DICITORWtt 


Fig.  59. 
The  tarsus,   metatarsus,   and   phalanges,   dorsal   surface. 


gg  HUMAN    ANATOMY. 

scaphoid,  anteriorly  by  a  triangular  facet  with  second  metatar- 
sal, and  laterally  with  internal  and. external  cuneiforms.  It  has 
no  muscles  attached. 

The  external  cuneiform  (os  cuneiforme  iertium),  in- 
termediate in  size,  and  more  regular,  articulates  posteriorly  with 
scaphoid,  anteriorly  with  third  metatarsal,  internally  with 
middle  cuneiform  and  second  metatarsal,  and  externally  with 
cuboid  and  fourth  metatarsal. 

Muscular  attachments  are  for  flexor  brevis  pollicis  and 
tibialis  posticus. 

The  metatarsal  bones  (ossa  metatarsalia)  have  the  same 
general  form,  as  the  metacarpal  bones  of  hand,  each  consisting 
of  shaft,  head  and  base. 

The  shaft  (corpus)  is  prismoid  and  curved,  with  concavity 
below,  convexity  above. 

The  head  (capitulum)  is  rounded  for  articulation  with 
phalanges,  and  has  tubercles  laterally  for  ligaments  and  a  groove 
below  for  tendon  of  long  flexor. 

The  base  (basis)  is  wedge-shaped  for  articulation  with  the 
tarsus  and  with  each  other. 

The  first  (os  metatarsale  I)  and  strongest  articulates  at 
base  with  internal  cuneiform,  at  head  with  phalanx  and  second 
metatarsal,  and  has  three  muscular  attachments :  for  tibialis 
anticus,  peroneus  longus  and  first  dorsal  interosseous. 

The  second  (os  metatarsale  II)  is  wedged  in  by  base  be- 
tween three  cuneiform  bones,  articulates  with  second  phalanx, 
first  and  third  metatarsi,  and  has  three  muscular  attachments : 
for  adductor  hallucis,  first  and  second  interosseous. 

The  third  (os  metatarsale  III)  articulates  with  external 
cuneiform  below  and  second  and  third  metatarsi  and  third 
phalanx,  and  has  four  muscular  attachments :  for  adductor  hal- 
lucis, first  plantar,  and  second  and  third  dorsal  interossei. 

The  fourth  (os  metatarsale  IV)  articulates  at  base  with  ex- 
ternal cuneiform  and  cuboid  and  at  extremity  with 'third  and 
fifth  metatarsal  and  fourth  phalanx,  and  has  four  muscular  at- 
tachments: for  adductor  hallucis,  third  and  fourth  dorsal,  and 
second  plantar  interossei. 

The  fifth  (os  metatarsale  V)  has  marked  tubercle  on  outer 
side.  It  articulates  with  cuboid,  fourth  metatarsal,  and  fifth 
phalanx,  and  has  five  muscular  attachments :  for  flexor  brevis 
minimi  digiti,  peroneus  brevis  and  tertius,  fourth  dorsal  and 
third  plantar  interosseus. 

The  phalanges  of  the  foot  (phalanges  dig  it  o  rum  pedis) 
have  same  general  characteristics  as  in  hand,  but  are  compressed 


OSTEOLOGY. 


97 


ku*a  mi.)  rtuiohf 


Fig.  60. 
The  tarsus,  metatarsus,  and  phalanges,  plantar  surface. 


98  HUMAN    ANATOMY. 

from  side  to  side  instead  of  from  before  backward ;  and  have  the 
following  nomenclature  applied :  first  or  proximal  phalanx 
(phalanx  prima)  ;  second  phalanx  (phalanx  secunda)  ;  ungual 
or  distal  phalanx  (phalanx  tertia) .  The  muscular  insertions  to 
first  row  are :  to  great  toe,  transversus  pedis,  extensor  brevis 
digitorum,  adductor,  abductor  and  flexor  brevis  hallucis;  to 
second,  first  and  second  dorsal  interosseus;  to  third,  third  dor- 
sal and  first  plantar  interosseus;  to  fourth,  fourth  dorsal  and 
second  plantar  interosseus;  to  fifth,  abductor  and  flexor  brevis 
minimi  digiti  and  third  plantar  interosseus.  To  second  row : 
to  great  toe,  flexor  and  extensor  longus  hallucis;  to  remaining 
toes,  extensor  longus  and  brevis  digitorum,  flexor  brevis  digi- 
torum and  lumbricales.  To  third  row,  or  ungual  phalanges: 
flexor  longus  and  extensor  longus  and  brevis  digitorum. 

The  ossific  centers  are  one  each  for  the  tarsus,  excepting  the 
os  calcis,  which  has  an  epiphysis  for  posterior  part,  and  two 
each  for  metatarsals  and  phalanges.  These  latter  are  arranged 
in  phalanges,  one  each  for  shaft  and  base,  and  in  metatarsals, 
one  each  for  shaft  and  head,  excepting  great  one,  which  has  one 
each  for  shaft  and  base. 

Sesamoid  bones  (ossa  sesamoidea)  are  small,  osseous 
masses,  cartilaginous  in  early  life,  developed  in  the  tendons  to 
relieve  pressure.  They  are  of  two  kinds — -those  over  articular 
surfaces  of  joints,  as  patella;  and  those  applied  to  the  surfaces 
of  bones,  as  in  tendon  of  peroneus  longus  in  the  groove  of 
cuboid  bone. 


OSTEOLOGY. 


99 


Name. 

Yertebr.e. 


Atlas   (3). 
Axis   (6). 

Seventh   Cervical. 


Lumbar    Verte- 
brae  (2). 

Sacrum    (35). 
15. 


10. 

6. 
4. 

Coccyx   (7). 


f'KANIAl, 

Bones. 
Occipital    (7). 


Parietal   (1), 


TABLE    OF    OSSIFICATION. 

Centers. 
Primary:  — 
1   for   each    lamina. 
1   for   each   process. 
1   for  body. 
Secondary  Centers:  — 

1  for  each  transverse  process. 

2  for  end  of  spinous  process. 
Additional    Plates: — ■ 

1  epiphyseal  plate  on  upper  and 
under  surface  of  bod  v. 


1   for  each  lateral  mass. 

1  epiphysis  for  anterior  arch. 

1  for  lower  part  of  body. 

1  for  each  lamina. 

2  for  lateral  processes. 

1   for  apex  of  odontoid  process. 
1   for  anterior  and  costal   part  of 
transverse  process. 

1   for    each    tubercle    of    superior 
articular   process. 

3 — 1  each  for  body 

and   upper  and  lower  epiphys- 
eal plate. 

2 — 1  for  each  arch. 


2  for  eacli  lateral  mass  of  the  fust 
three  vertebrae. 

Each  lateral  surface  has  one  epi- 
physeal articulation  and  ad- 
joining edge. 

1   for  each  piece. 

1. 

2. 

3. 

4. 


4  for  tabular  or  epi-oceipital. 
1    for   each    condylar    portion. 


1   for  basilar  portion. 
From  membrane. 

^iiiL'le  center  at  parietal   eminence 


Time  of 
Appearance. 

6th  week. 
8th  week. 
16th  year. 


21st  year. 

All  unite  by  30th 

year. 
8th  week. 
1st  year. 
6th  month. 

6th    fetal    month. 

6th  fetal  month  : 
joins  5th  or 
6th    rear. 


8th  or  9th  week. 
16th     year,     and 

un'tes    18th   or 

20th    vear. 
6th  or  8th  month; 

joins  2d  to  6th 

vear. 


18t.li 
year, 


to       25th 


Birth. 

5th  to  10th  year. 
10th  to  15th  year. 
15th  to 20th  vear. 


8th  fetal  week. 

-1  tli  in  6th  year: 
joined  In  sphe- 
noid 18th  to 
25t'i    year. 

7th   to   8th    fetal 

week. 


100 


HUMAN    ANATOMY. 


"Name. 
Frontal    (2). 

Temporal    (10). 
Sphenoid    (14). 


Centers. 
1  for   each   lateral   portion. 
From  membrane. 

1  for  squamous  process. 

1  for  auditory  process. 
6  for  petromastoid. 

2  for  styloid  process. 
8  for  postsphenoid. 

1  for    each   greater   wing   and   ex- 
ternal pterygoid  plate. 

1  for  each  internal  pterygoid  plate. 

2  for  posterior  part  of  body. 


1  for  each  lingula. 
6  for  presphenoid: — 

1  for  each  lesser  wing. 

2  for  anterior  portion  of  body. 
1  for  each   sphenoturbinal. 


Ethmoid  (3), 


1  for  each  lateral  mass. 
1  for  lamella. 


Face. 
Nasal.  1   for  each  bone. 

Superior  Maxillae 

(4).  1  premaxilla. 

1  prepalatine  portion. 


Lachrymal. 
Malar. 
Palate. 

Inferior    Turbi- 
nated. 


1  maxillary  portion. 

1  malar  portion. 

A  single  center. 

Single  center. 

Single  center  at  junction  of  plates. 

Single  center. 


Vomer.  Single  center,  but  two  laminae. 

Inferior   Maxilla.    Probably  several  centers;   at  birth 
consists  of  two  halves. 


Body. 
Hyoid   (5). 


1  for  body  and  for  each  cornu. 


Time  of 
Appearance. 

7th  to  8th  week. 

United     by     4th 
year. 

2d  month. 

Later. 

5th  or  6th  month. 


1  for  base  ap- 
pears before 
birth  and  one 
after    birth. 

Appear  from  8th 
week  to  third 
year,  and  union 
of  all  parts  is 
accom  p  1  i  s  h  e  d 
by  the  20th 
year,  and  with 
occipital,  18th 
to   25th   year. 

4th  to  5th  fetal 
month. 

Unite  about  2d 
year. 


6th   week. 

Very  early. 

Antrum  appears 
about  fourth 
fetal   month. 


7th  week. 
6th  week. 
2d   fetal  month. 

Middle  of  fetal 
life. 

8th  week. 

Very  early,  be- 
ing second  in 
order. 


3     months     after 
birth. 


OSTEOLOGY. 


101 


Name. 
Sternum    (6), 

Ribs  (3). 


Upper 
Extremity. 

Clavicle    (2). 
Scapula   ( 7 ) . 


Humerus   ( 7 ) . 


Ulna   (3). 
Radius    (3). 


Carpus. 


Centers. 

1   for  manubrium. 

4  for  gladiolus. 

1  for   ensiform   appendix. 

1  for  each  shaft,  head,  and  tuber- 
cle, excepting  the  last  two, 
which  have  but  2,  the  tuber- 
cles being  absent. 


1  for  shaft. 

1  for  sternal  extremity. 

1  for  body. 

2  for  coracoid  process. 

2  for  acromion   process. 

1  for  posterior  border. 

1  for  inferior  angle. 

1   for  shaft. 

1   for  head. 

1   for  tuberosities. 

1   for  radial  head. 


1  trochlear  portion. 

1  for  each   condyle. 

1  for  shaft. 

1  for  olecranon. 

1  for  lower  extremity. 

1  for  shaft. 

1  for  upper  extremity. 


1  for  lower  extremity. 


Each   lias  single  center:  — 
I  •-  magnum. 
I  'nciforni. 
Cuneiform. 

Trapezium  and  semilunar. 
Scaphoid. 
Trapezoid. 
1'isiform. 


Time  of 
Appearance. 
Middle     of     fetal 
life. 

Before  vertebrae. 
Epiphysis  for 
tubercle  ap- 
pears from 
16th  to  20th 
year,  and 
unites  about 
25th. 


About  30th  day. 
2d  month. 


Completed  be- 
tween 20th  and 
25th  year. 

!-'tli   week. 


Upper  extremity 
ossifies  2d  to 
4th  year. 

Complete      about 

20th  year. 
8th  week. 
10th  year. 
4th  year. 
Soon     after     hu- 
merus. 
5th    year;    unites 

17th     to     18th 

year. 
2d    year;     unites 

20th  year. 
Upper    extremity 

joins  16th  year; 

lower,     20  th 

year. 

1st  year. 
1st  year. 
3d  year. 
5 tli  year, 
fitll  year. 
8th  year. 
12th  year. 


102 


HUMAN    ANATOMY. 


Name. 
Metacarpus    ( 2 ) . 


Phalanges    ( 2 ) . 


Centers. 
Centers  for  each: — 
1  for  shaft  and 

1  for   each  distal   extremity  ex- 
cept   thumb,    which    has    one 
each  for  shaft  and  base. 
1  each  for  shaft  and  base. 


Time  of 
Appearance. 

8th  or  9th  week. 
3d       year,       and 

unites       about 

20th  year. 
8th      week,      and 

unites    18th   to 

20th  year. 


Lower 

Extremity. 

Os       Innominata 

(8). 

3  Primary: — 

Ilium. 

Same     as     verte- 
•   brse,   6th  week. 

Ischium. 

3d  month. 

Pubes. 

4th  or  oth  month. 

5  Secondary: — • 

1  crest  of  ilium. 

Puberty. 

1  anterior  inferior 

spinous  proc- 

ess. 

" 

1   tuber  ischii. 

it 

1  symphysis  pubis. 

" 

1  acetabulum. 

13th  or  14th year; 
completed  25th 
year. 

Femur  (5). 

1  for  shaft. 

5th  week. 

1  for  lesser  trochanter. 

End  of   1st  year 

1  for  great  trochanter. 

9th    fetal    month. 

1  for  lower  extremity. 

4th  year. 

1  for  upper  extremity. 

13th  or  14th  year. 

Inferior     extrem- 

ity.     The    last 

is     not    united 

before  the  20th 

year. 

Patella. 

Single  center. 

3d  to  6th  year; 
completed 
about    puberty. 

Tibia  (3). 

1  for  shaft. 

7th  week. 

1  upper  extremity. 

Birth  ;  unites 
20th  year. 

1  •  lower  extremity. 

2d  year ;  unites 
18th  year. 

Fibula   (3). 

1  for  shaft. 

8th   fetal  week. 

1  upper  extremity. 

4th  year. 

1  lower  extremity. 

2d  year ;  the 
lower  unites 
first  —  about 
20th  year. 

OSTEOLOGY. 


103 


Name. 


Tarsus. 


Metatarsus. 


Centers. 

os  calcis:  — 

1  for  body  and 

1  for  posterior  extremity. 

each  for  the  following:  — 

Cuboid. 

Astragalus. 

Scaphoid. 

Internal  cuneiform. 

Middle   cuneiform. 

External  cuneiform. 


1  each  for  shaft 

and  digital  extremity, 
except  great  toe,  which  is 
same  as  thumb. 
Phalanges    (2).       1  each  for  shaft  and  proximal  ex- 
tremity. 


Time  of 
Appearance. 

6th    fetal    month. 


9th  month. 
7th  month. 
4th  year. 
3d  year. 
4th  year. 
1st  year. 
7  th  week. 
3d  year. 


ARTICULATIONS  AND  LIGAMENTS. 


The  bones  of  the  skeleton  are  connected  together  by  articu- 
lations or  joints. 

These  consist  essentially  of  the  expanded  extremities  of 
bones,  covered  with  cartilage,  often  separated  by  interarticular 
fibrocartilage,  held  together  by  ligaments,  and  lined  by  synovial 
membrane. 

The  bone  entering  into  the  articular  lamella  differs  from 
ordinary  bone  by  its  extreme  density,  without  Haversian  canals, 
its  lacunae  being  much  larger,  and  without  canaliculi.  It  is  not 
perforated  by  blood-vessels. 

Cartilage  is  a  whitish,  highly  elastic,  non-vascular  struc- 
ture, forming  in  the  fetus  the  greater  part  of  the  skeleton,  and 
found  in  the  adult  chiefly  in  the  joints,  the  walls  of  the  thorax, 
and  certain  orifices,  as  the  nostrils,  ears,  etc. 

It  is  either  temporary,  becoming  ossified  later,  or  perma- 
nent, remaining  unossified.  The  latter  is  divided  into  three 
varieties:  articular.,  in  joints  covering  the  ends  of  the  bones; 
costal,  forming  part  of  the  thorax;  and  reticular,  arranged  in 
plates  or  lamellae  to  maintain  the  shape  of  parts. 

Fibrocartilage  consists  of  a  mixture  of  cartilaginous  with 
white  fibrous  tissue.     There  are  four  varieties: — 

(a)  Inter  articular,  interposed  between  the  joint  surfaces; 

(b)  Connecting,  binding  bones  together  as  in  pubes; 

(c)  Circumferential,  deepening  cavities,  as  glenoid  cavity  of 
shoulder;  and 

(d)  Stratiform,  lining  grooves  for  tendons. 

Synovial  membranes  are  of  three  kinds:  articular,  lining 
the  cavities  of  movable  joints  throughout  except  the  surface  of 
the  cartilage;  bursal,  irregular  cavities  interposed  at  convenient 
positions  to  alleviate  friction;  from  their  contents  they  may  be 
either  mucous  or  synovial;  and  vaginal  synovial  membranes,  or 
sheaths,  surrounding  tendons  and  diminishing  friction. 

Synovia  is  a  transparent,  viscid  liquid,  albuminous  in  its 
nature. 

The  articulations  consist  of  three  (3)  classes:  diarthrosis, 
movable;  synarthrosis,  immovable;  and  amphiarthrosis,  mixed. 

(104) 


ARTICULATIONS    AND    LIGAMENTS.  I(j5 

1.  The  diarthrosis  are  subdivided  into: — 

Arthrodia,  gliding  joint,  as  superior  tibiofibular; 

Enarthrosis,  ball-and-socket  joint,  as  shoulder  and  hip; 

Ginglymus,  hinge-joint,  as  knee  and  ankle; 

Troehoides,  a  ring  surrounding  a  pivot,  as  atloaxoid  joint  and 
superior  radioulnar. 

Condyloid,  elliptical  cavity  receiving  an  ovoid  head,  as  wrist  joint. 

Reciprocal  reception,  a  concavoconvex  articulation,  as  carpometa- 
carpal joint  of  thumb. 

8.  Synarthrosis,   surface   immovably    connected   by   fibrous 
membrane  without  synovial  membrane. 
They  are  divided  into: — 

Sutura,  bones  interlocking  with  one  another; 

Schindylesis,  a  fissure  in  one  bone  receiving  a  plate  of  bones,  as 
between  vomer  and  sphenoid; 

Gomphosis,  a  socket  with  a  pivot  inserted,  as  in  alveolar  cavities 
for  teeth. 

Synchondrosis,  a  temporary  joint  in  which  the  connecting  medium 
is  cartilage. 

The  sutura  may  be  either  true,  sutura  vera,  or  false,  sutura 
notha,  the  former  having  three  divisions :  dentata,  tooth-like 
processes,  as  interparietal  suture;  serrata,  saw-like  edges,  as 
interfrontal  suture;  limbosa,  dentated  processes  and  beveled 
margins,  as  frontoparietal ;  the  latter  two  divisions : — 

Squamosa,  overlapping  beveled  margins,  and 

Harmonia,  by  union  of  roughened  surfaces,  as  intermaxillary 
suture. 

3.  AmpliiartJirosis,  bony  surfaces  connected  by  fibroearti- 
lage,  with  or  without  synovial  membrane,  as  between  vertebral 
bodies,  and  pubic  symphysis. 

MOTIONS  IN  Joints. — Joints  admit  of  four  (4)  distinct 
varieties  of  motion: — 

(a)  Gliding   movement,    between    contiguous    surfaces; 

(6)  Angular  movement,  as  flexion,  extension,  adduction  and  ah 
duction; 

[c)  (  ircumduction,  as  in  true  enarthrosis; 

(d)  Rotation  on  its  own  axis,  as  between  the  atlas  and  axis. 

Ti;.m  I'Oito.M  axi  LLARY,  or  1  em | M n'oiiuiiid ibular  articulation 
(articulatio  mandibidaris) ,  is  formed  by  condyle  of  lower  jaw, 
below  articulating  with  glenoid  cavity  of  the  temporal  bone  and 
eminentia  articularis  above.     It  is  a  double  arthrodial  joint. 

Ligaments. — External  Lateral  (ligamentum  t'emporomm- 
dibulare).  Origin,  tubercle  on  outer  edge  of  zygoma  ;  insertion, 
outer  Bide  of  neck  of  condyle. 


106  "  HUMAN    ANATOMY. 

Internal  Lateral  (ligamentum  sphenomandibulare) . — - 
Origin,  spinous  process  of  sphenoid;  insertion,  lower  circumfer- 
ence of  inferior  dental  foramen. 

Capsular  (capsula  articularis) . — Origin,  circumference  of 
articulation;  insertion,  neck  of  condyle. 

Interarticular  fibrocartilage  (discus  articularis)  is  within 
cavity;  external  pterygoid  muscle  attached  to  its  inner  edge. 

Synovial  membrane  is  divided  into  two  by  cartilage. 

Intermaxillary  ligament  passes  from  external  pterygoid 
process  to  coronoid. 

Styloniaxillary  or  Stylomandibular  Ligament  (ligamentum 
stylo  mandibular  e) . — Origin,  styloid  process;  insertion,  inner 
surface  of  angle  of  jaw.  Nerves  are  derived  from  the  auriculo- 
temporal and  masseteric  branches  of  the  inferior  maxillary. 

Articulations  of  Vertebral  Column. — These  are  formed 
between  the  contiguous  surfaces  of  the  vertebral  bodies  and 
articular  processes,  inclosed  in  capsular  ligaments,  and  con- 
nected with  the  following  ligaments : — 

The  anterior  common  ligament  (ligamentum  longitudinale 
anterius)  extends  from  the  front  of  the  body  of  the  axis  down 
the  anterior  surface  (ventral)  of  the  spine  to  the  sacrum,  being 
expanded  opposite,  and  attached  to  each  intervertebral  connect- 
ing fibrocartilage; 

The  posterior  common  ligament  (ligamentum  longitudinale 
posterius)  descends  along  posterior  surfaces  (dorsal)  of  bodies 
from  axis  to  sacrum  within  spinal  canal.  It  also  expands 
opposite  and  adheres  to  intervertebral  substance; 

Intervertebral  substance  (fibrocartilagines  intervertebrales) , 
disks  of  varying  size,  twenty-seven  in  number,  composed  of 
decussating  fibers  of  fibrocartilage,  arranged  in  crescentic 
laminge  with  central,  semipulpy  substance,  separate  the  verte- 
bras; 

Ligamenta  subflava  (ligamenta  flava,  ligamenta  ihtercru- 
ralia)  descend  in  pairs,  twenty-three  on  either  side,  from  one 
lamina  to  another,  from  axis  to  sacrum,  inclosing  spinal  canal; 

Supraspinous  ligament  (ligamentum  supraspinal^)  strong 
cord  descending  from  one  vertebra  to  another,  from  vertebra 
prominens  (seventh  cervical)  to  sacrum.  Its  continuation  in 
cervical  region  forms  ligamentum  nucha; 

Interspinous  (ligamenta  inters  pinalia)  stretch  between 
spinous  processes  throughout  dorsal  and  lumbar  regions; 

Intertransverse  (ligamenta  mtertransversaria) ,  between 
transverse  processes  in  lower  dorsal  and  lumbar  regions. 


ARTICULATIONS    AND    LIGAMENTS.  107 

The  arteries  are  derived  from  ascending  cervical  and  verte- 
bral in  cervical,  intercostals  in  dorsal,  and  lumbars  in  lumbar 
regions. 

The  nerves  are  from  spinal  nerves  in  each  region. 
Atloaxoid  or  atlaxtoaxoideax  articulation  (articula- 
tio  atlantoepistrophica)  consists  of  of  four  joints,  the  two  lateral 
joints  being  arthrodia,  and  that  between  the  odontoid  process 
and  arch  of  atlas  and  transverse  ligament — a  diarthrosis  rota- 
toria  being  double,  one  in  front,  atlo-odontoid,  and  one  behind, 

bdontotransverse.     The  ligaments  are: — 

Anterior  atloaxoid,  or  anterior  atlantoaxial,  two — super- 
ficial and  deep,  connecting  anterior  borders  together; 

Posterior  atloaxoid,  or  posterior  atlantoaxial,  connecting 
the  arches  of  the  atlas  and  axis  posteriorly,  and  pierced  laterally 
by  the  second  spinal  nerve; 

Capsular  (eapmlce  articulares) ,  two,  connecting  the  articu- 
lating processes  laterally,  and  lined  with  synovial  membrane; 

Transverse,  or  cruciform  (ligamentum  transversum  atlan- 
tis),  arises  from  the  tubercle  on  one  side  of  the  lateral  mass, 
passes  across  the  back  of  odontoid  process  to  be  inserted  into 
the  opposite  tubercle. 

The  arteries  are  from  vertebral,  nerves  from  second  cervical, 
or  from  loop  between  it  and  suboccipital. 

Occipitoatlotd  (articulatio  atlanto-Oi  ipitalis). — Anterior 
occipitoatloid  (membrana  atlanto-occipitalis  anterior) — two, 
superficial  and  deep,  connecting  the  tubercle  and  upper  border 
of  anterior  arch  or  atlas  with  basilar  process  and  margin  of 
foramen  magnum  of  occiput. 

Posterior  occipitoatloid,  or  occipitoatlantal  ligament  (mem- 
brana atlanto-occipitalis  posterior — membranous),  connects  the 
upper  border  of  posterior  arch  of  atlas  with  posterior  margin 
of  foramen  magnum. 

Lateral  ligaments,  two  bands  connecting  transverse  process 
of  atlas  with  jugular  process  of  occipital. 

Capsular  ligaments  (capsules  articulares)  connect  the  artic- 
ular processes  of  atlas  with  condyles  of  occiput. 

The  arteries  are  from  rertebral;  nerves,  from  suboccipital. 
OCCIPITOAXOID. — Occipitoaxoid  is  a  broad   hand,  the  con- 
tinuation of  posterior  common   ligament,  extending   from   the 
body  of  the  axis  to  basilar  groove  of  occipital. 

odontoid,  or  check  (ligamentum  alaria),  pass  upward  and 
outward  from  the  summit  of  tin,'  odontoid  process,  to  he  inserted 
into  the  inner  side  of  the  occipital  condyles. 


108  HUMAN    ANATOMY. 

Ligamentum  suspensorium,  or  central  occipito-odontoid 
{ligamentum  apices  dentis),  arises  from  the  center  of  the  trans- 
verse ligament  at  the  apex  of  the  odontoid  process,  and  passes 
upward,  to  be  inserted  into  the  anterior  margin  of  the  foramen 
magnum. 

Occipitocervical,  or  cervicobasilaris  {membrana  tectoria, 
apparatus  ligamentosus  colli,  posterior  occipitoaxoid  ligament), 
arises  from  the  bodies  of  the  third  cervical  and  axis,  and  is 
inserted  into  the  basilar  groove  of  occipital. 

The  arteries  are  from  vertebral;  the  nerves  from  suboc- 
cipital. 

Capsular  Ligaments. — Throughout  the  spine  the  articula- 
tions between  the  facets  of  the  articular  processes  are  surrounded 
by  capsular  ligaments,  making  twenty-five  pairs  in  all. 

Costovertebral  Articulations  {articulationes  costoverte- 
brales). — The  costovertebral  have  each  a  double  arthrodia  be- 
tween the  head  of  the  rib  and  the  bodies  of  the  two  adjacent 
vertebrae,  except  the  first,  tenth,  eleventh  and  twelfth  ribs, 
which  have  each  but  a  single  joint. 

Anterior  Costovertebral,  or  Stellate  Ligament  {ligamentum 
capituli  costm  radiatum). — Origin,  head  of  the  rib;  insertion, 
into  body  of  vertebra  above  and  below,  and  interarticular  carti- 
lage between. 

Interarticular  costovertebral  {ligamentum  capituli  costw 
interarticulare)  is  within  the  capsular  ligament,  from  the  crest 
on  the  head  of  the  rib  to  the  intervertebral  substance. 

Capsular  ligament  {capsula  articularis)  surrounds  the  artic- 
ular surfaces. 

Costotransverse  articulations  are  united  by  three  ligaments 
— anterior,  middle,  and  posterior  costotransverse  ligaments — 
extending  between  the  tubercles  of  the  ribs  to  the  transverse 
process  below.  Arteries,  the  intercostals ;  nerves,  anterior 
branches  of  spinal. 

Costosternal  Articulations  (articulationes  sternocos- 
tales). — These  are  connected  by  arthrodia  excepting  the  first, 
which  is  a  synarthrodia. 

Anterior  chondrosternal  ligaments  {ligamentum  sternocos- 
tal radiatum)  connect  the  chondral  and  sternal  surface  in 
front ; 

Posterior  chondrosternal  {ligamentum  sternocostal^  radia- 
tum) connect  them  behind. 

Capsular  ligaments  {capsula  articularis)  surround  all,  and 
synovial  membranes  are  present  in  all  but  the  first,  while  the 
second  has  an  interarticular  cartilage  interposed. 


ARTICULATIONS    AND    LIGAMENTS.  1Q9 

The  chondroxiphoid  (Ugamentum  costoxiphoidea)  ligament 

connects  the  cartilage  of  the  seventh  and  sometimes  the  sixth 
rib  with  the  xiphoid  appendix. 

Interchondral  and  Costochondral  Articulations  (articula- 
tiones  interchondrales) . — The  ribs  are  connected  with  their  car- 
tilages by  the  periosteum  covering  them.  The  cartilages  of  the 
sixth,  seventh,  and  eighth  ribs,  and  sometimes  the  fifth  and 
ninth,  are  connected  by  external  and  internal  interchondral 
ligaments  (ligamenta  intercostalia  externa  et  interna),  held 
together  by  capsular  ligaments  and  lined  with  synovial  mem- 
brane. 

Ligaments  of  Sternum. — The  first  and  second  portions 
of  the  sternum  are  articulated  by  an  amphiarthrodial  joint, 
sometimes  a  diarthrodial  joint,  connected  by  the  external  inter- 
sternal  and  internal  intersternal  ligaments,  and  lined  with 
synovial  membrane. 

The  third  portion,  or  enisform  cartilage,  is  united  to  the 
gladiolus  by  a  synarthrodia!  joint. 

THE    THORAX. 

The  thorax  is  a  conical  osteocartilaginous  framework, 
formed  by  the  dorsal  vertebrae  behind,  the  ribs,  intercostal  mus- 
cles, and  costal  cartilages  laterally,  and  the  sternum   in  front. 

The  apex,  or  superior  opening  (apertura  thoracis  superior), 
is  bounded  behind  by  the  first  dorsal  vertebra,  laterally  by  the 
first  rib,  and  in  front  by  the  npper  border  of  the  sternum. 

It  transmits  the  following  structures: — 

Esophagus,  trachea,  thoracic  duct  (on  the  left  side),  lymphatic 
vessels  of  right  side  of  chest  and  of  surface  of  liver,  innominate  artery 
(right  side),  left  common  carotid  artery,  left  subclavian  artery,  right 
and  left  superior  intercostal  arteries,  right  and  left  internal  mammary 
arteries,  thyroidea  ima  artery  (if  present),  right  and  left  inferior  thy- 
roid veins,  right  and  left  innominate  veins,  right  and  left  phrenic  nerves, 
right  and  [eft  pneumogastric  nerves  and  their  cardiac  branches,  left 
recurrent  laryngeal  nerve,  right  and  left  first  dorsal  nerves,  right  and 
left  sympathetic  nerves  and  their  cardiac  branches,  apices  of  lungs  and 
pleurae,  remains  of  thymus,  and  deep  cervical  fascia  passing  to  peri- 
cardium. 

The  longus  colli,  Bternohyoides  and  sternothyroides  on  both  Bides 
also  pass  I  trough  it. 

The  inferior  opening  {apertura  thoracis  inferior)  is  formed 
by  the  last  dorsal  vertebra  behind,  the  last  rib  laterally,  and  the 
ensiform  cartilage  in  front.     It  Is  filled  in  by  the  diaphragm. 

The  cavity  (carum  thoracis)  of  the  thorav  contains  the 
following  structures:   the  heart  and  great  vessels,  trachea,  hron- 


110  HUMAN    ANATOMY. 

chi  and  lungs,  azygos  and  bronchial  veins,  internal  mammary 
arteries,  pneumogastric,  phrenic  and  splanchnic  nerves,  thoracic 
duct,  esophagus,  lymphatic  vessels  and  glands  (vide  medias- 
tinum). 

Spine  and  Pelvis. — Sacrovertebral  articulation.  In  addi- 
tion to  those  of  the  spine,  given  above,  there  are  two  ligaments 
connecting  the  last  lumbar  vertebra  with  the  sacrum : — 

Lumbosacral  ligament,  arising  from  the  transverse  process 
of  the  last  lumbar  vertebra,  and  inserted  into  the  base  of  the 
sacrum ; 

Iliolumbar  ligament  (lig amentum  Violumbale),  arising 
from  the  apex  of  the  transverse  process  of  the  last  lumbar  verte- 
bra, and  inserted  into  the  crest  of  the  ilium.  The  arteries  are 
from  last  lumbar,  iliolumbar  and  lateral  sacral.  The  nerves 
are  branches  of  fourth  and  fifth  lumbar  and  sympathetic. 

Sacroiliac  articulation  (articulatio  sacroiliaca) ,  between  the 
articular  surfaces  of  the  sacrum  and  ilium,  is  an  amphiarthrodial 
joint  connected  by 

The  anterior  sacroiliac  ligament  (ligamenia  sacroiliaca  on- 
teriora),  crossing  between  anterior  surfaces  of  the  two  bones; 

Posterior  sacroiliac  ligament  (ligamentum  sacroiliacum 
posterius) ,  the  stronger,  passes  in  different  directions  between 
the  posterior  surfaces  of  the  two  bones,  firmly  binding  them 
together.  One  of  these,  stronger  than  the  others,  passes  from 
the  posterior  superior  spinous  process  to  the  third  sacral  trans- 
verse process.     It  is  called 

The  oblique  sacroiliac  ligament  (ligamentum  sacroiliacum 
posterius  longum). 

The  arteries  are  from  gluteal,  sacral,  spinal  and  iliolum- 
bar; the  nerves  from  lumbosacral  and  posterior  sacral  cords. 

Sacroiscliiatic  Articulation. — -The  os  innominatum  and  sa- 
crum are  united  by  two  important  ligaments — the  great  sacro- 
sciatic  (posterior)  ligament,^  and  the  lesser  sacrosciatic  (anter 
rior)  ligament. 

The  great  sacrosciatic  ligament  (ligamentum' sacrotubero- 
sum)  arises  from  the  fourth  and  fifth  transverse  tubercles  of 
the  sacrum,  from  spine  of  ilium,  sacrum  and  coccyx,  and  passes 
downward,  outward  and  forward,  to  be  inserted  into  the  inner 
margin  of  the  tuberosity  of  the  ischium,  being  prolonged  for- 
ward as  the  falciform  ligament  (processus  fahiformis)  protect- 
ing the  internal  pudic  veins  and  nerves. 

It  converts  the  sacrosciatic  notch  into  the  lesser  sacro- 
sciatic foramen,  transmitting  the  obturator  internus  muscle  and 
nerve,  the  internal  pudic  vessels  and  nerves. 


ARTICULATIONS    AM)     LKiA.M  K.X'I'S. 


Ill 


The  lesser  sacrosciatic  ligament   (ligamentum  sacrospino- 

sum)  arises  from  the  lateral  margin  of  the  sacrum  and  coccyx, 
and  is  inserted  into  the  spine  of  the  ischium.  It  converts  the 
sacrosciatic  notch  into  the  greater  sacrosciatic  foramen  (foramen 
i  xhiadicum  majus),  transmitting  the  pyriformis  muscle,  gluteal 
vessels,  superior  gluteal  nerve,  sciatic  vessels  and  nerves,  and  the 
internal  pudic  vessels  and  nerves. 

Sacrococcygeal  articulation  (symphysis  sacrococcygea)  is 
an  amphiarthrodial  joint,  resembling  the  vertebral,  having  an 
interarticular  fibrocartilage,  and  connected  together  by 


Pig.  61. 


1,     manubrium;     2,     gladiolus;     ?,,     xiphoid     appendix;     4,     first    dorsal 
vertebra;    5,    last   dorsal    vertebra;    6,    first   rib. 


An  anterior  sacrococcygeal  ligament  (ligamentum  sacra- 
coccygeum  anterius),  and 

A  posterior  sacrococcygeal  ligament  (ligamentum  sacro- 
coccygeum  posterius),  continuations  respectively  of  the  anterior 
and  posterior  common  ligament. 

Lateral  sacrococcygeal,  intertransverse  (ligamentum  sacro- 
coccygeum  laterale),  and  intercornual  ligaments  connecting  the 
rudimentary  tran  verse  processes  and  the  cornua  together. 

The  arteries  are  from  lateral  and  median  sacral: 

Tin-  nerve  branches  of  coccygeal,  fifth  sacral,  and  posterior 
<li\i-ions  of  fourth  sacral. 


112  HUMAN    ANATOMY. 

Pubic  Articulation. — This  is  an  amphiarthrodial  joint, 
known  also  as  the  symphysis  pubis  (symphysis  ossium  pubis) . 

It  is  connected  by  the 

Anterior  pubic  ligament  (Jig amentum  pubicum  anterius) 
in  front; 

Superior  pubic  ligament  (Jigamentum  pubicum  superius) 
above ; 

Posterior  pubic  ligament  (Jigamentum  pubicum  posterius) 
behind ; 

Subpubic  ligament  (lig amentum  arcuatum  pubis)  below, 
forming  the  boundary  of  the  pubic  arch. 


FIG.  62. 

A  A,  anteroposterior  diameter;  B  B,  transverse  diameter;  C  C, 
oblique  diameter;  1,  sacroiliac  ligament;  2,  anterior  or  lesser  sacro- 
sciatic   ligament;   3,   posterior  or  great  sacrosciatic   ligament. 

Within  the  joint  an  interposed  fibroeartilage,  or  interpubic 
disk  (lamina  fibrocartilaginea  interpubica) ,  separates  the  bones. 

The  obturator  membrane,  or  ligament,  closes  the  obturator 
foramen,  and  affords  attachment  for  the  external  and  internal 
obturator  muscles  and  allows  passage  at  its  upper  outer  part, 
for  the  obturator  vessels  and  nerves. 


THE    PELVIS. 

The  pelvis  is  a  strong,  bony  basin,  formed  at  the  lower  end 
of  the  vertebral  column  by  the  articulation  of  the  sacrum  and 
coccyx  posteriorly  with  the  ossa  innominata  laterally. 

It  is  divided  into  a  false  and  true  pelvis  by  the  iliopectineal 
line. 

The  false  pelvis  (pelvis  major)  is  situated  above  the  ilio- 
pectineal  line,    and   corresponds   to   the   expanded   iliac   fossae, 


ARTICULATIONS    AND    LIGAMENTS.  113 

being  bounded  laterally  by  the  ossa  ilii,  and  having  in  front  and 
behind  wide  intervals. 

The  true  pelvis  (pelvis  minor)  includes  all  that  portion 
below  the  linea  iliopeetinea,  and  presents  a  cavity,  superior  cir- 
cumference or  inlet,  and  an  inferior  circumference  or  outlet, 

The  inlet  (apertura  pelvis  superior)  is  heart-shaped,  being 
bounded  behind  by  the  promontory  of  the  sacrum,  laterally  by 
the  linea  iliopeetinea,  and  in  front  by  the  crest  and  spine  of 
the  pubes. 

Its  principal  diameters  in  the  female  are : — 

Anteroposterior  or  conjugate  (conjugata) ,  from  symphysis  to 
vertebral  angle,  four  and  three-fourths  inches;  transverse  (diameter 
transversa)  across  the  widest  part,  five  and  one-fourth  inches;  and  ob- 
lique (diameter  obliqua) ,  from  the  iliopectineal  eminence  in  front  to 
the  sacroiliac  sympnysis  behind,  five  inches;  the  anatomical  conjugate 
(conjugata  anatomica)  from  the  sacrovertebral  angle  to  the  top  of  the 
symphysis  and  measures  about  four  and  three-fifths  inches;  the  true, 
available  or  obstetric  conjugate  (conjugata  gyiurcologica)  is  taken  from 
the  sacrovertebral  angle  to  the  nearest  point  upon  the  symphysis,  and 
in  the  female  averages  about  four  and  three-eighths  inches.  In  the 
male,  these  measurements  are  about  three-fourths  of  an  inch  less  in 
every  diameter. 

It  transmits  the  following  structures: — 

Viscera  and  Ducts. 

1.  Small   intestines.  -3.  Urachus    and    obliterated   hypo- 

2.  Rectum.  gastric  arteries. 

3.  Vasa      deferentia      (in      male),       6.  Uterus    (pregnant). 

round  ligaments    (in  female).       7.  Bladder    (distended). 

4.  Ureters.  8.  Peritoneal  coverings. 

Vessels. 

1.  Superior  hemorrhoidal.  6.  Obturator     (from    deep    epigas- 

2.  Internal  iliac.  trie). 
:>,.  Sacra  media.                                          7.  Ovarian. 

4.   Iliolumbar.  8.  Pubic    branches    from    external 

.">.    Brancb.ee   of   vasa   intestini   ten-  epigastric  arteries. 

uia.  9.  Lymphatic  vessels. 

Nerves. 

1.  Sympathetic  :5.  Obturator. 

1.   Branches        from        hypogastric       4.  Lumbosacral  cord. 

pleXUS. 

The  cavity  of  the  pelvis  is  bounded  behind  by  the  sacrum 
and  coccyx,  in' fr-mf  by  the  symphysis,  and  laterally  by  the  body 
of  the  ischium,  forming  a  curved  canal,  widest  in  the  middle. 

8 


H4  HUMAN    ANATOMY. 

It  contains,  in  the  recent  state,  the  organs  of  generation,  rectum, 
bladder,  and  their  vessels,  nerves,  ducts,  etc.  Its  axis  corre- 
sponds to  the  concavity  of  the  sacrum  and  coccyx. 

Its  depth  in  front,  at  the  symphysis,  is  about  one  and  a 
half  inches  in  the  middle  axial  line,  three  and  a  half  behind,  in 
males  four  and  a  half  to  possibly  five  and  a  half. 

The  outlet  of  the  pelvis  (apertura  pelvis  inferior)  is 
bounded  by  three  prominences,  the  tuber  ischii  laterally  and  the 
coccyx  behind ;  separated  by  three  notches,  the  subpubic  arch  in 
front  and  the  sacrosciatic  notches  posteriorly. 

Its  principal  diameters  are :  transverse,  three  and  a  half 
inches  in  male,  four  and  three-fourths  in  female;  anteropos- 
terior, three  and  three-fourths  in  male,  four  and  one-half  in 
female. 

In  the  erect  position  the  pelvis  is  placed  at  an  angle  of 
from  sixty  to  sixty-five  degrees  with  the  ground. 

Differences  of  Sex. — The  male  pelvis  is  characterized  by 
the  strength  of  the  bones,  by  prominent  muscular  impressions, 
by  the  depth  and  narrowness  of  the  cavity,  the  large  obturator 
foramen,  and  the  acute  angle  of  the  subpubic  arch. 

The  female  pelvis  is  characterized  "liytlfe  lightness  of  the 
bones,  the  slight  muscular  impressions,  by  the  shallow,  expanded 
iliac  fossae,  the  increased  size  of  the  cavity  in  every  diameter, 
and  the  obtuse  angle  of  the  subpubic  arch. 

ARTICULATIONS     OF     THE    UPPER    EXTREMITY. 

The  sternoclavicular  articulation  (articulatio  sternodavicu- 
laris)  is  an  arthrodial  joint,  formed  between  the  sternal  end  of 
the  clavicle  and  the  sternum  and  first  rib,  being  divided  into 
two  cavities  by  an  interarticular  fibrocartilage.  Its  ligaments 
are: — 

Anterior  sternoclavicular  (ligementum  sternoclavicular ~e) 
is  a  broad  band  passing  between  the  articular  margins,  attached, 
to  the  interarticular  cartilage  and  two  synovial  membranes,  and 
forming  the  front  part  of  the  capsular  ligament; 

Posterior  sternoclavicular  passes  over  the  posterior  aspect  of 
the  joint  and  corresponds  to  the  former ; 

Interclavicular  {ligamentum  inter  claviculare)  passes  from 
the  sternal  end  of  the  clavicle  on  one  side  across  the  suprasternal 
notch  to  the  clavicle  of  the  opposite  side ; 

Costoclavicular,  or  rhomboid  (ligamentum  costo clavicu- 
lare), passes  from  the  rhomboid  impression  on  the  inferior  sur- 


ARTICULATIONS    AM)    LIGAMENTS. 


115 


face  of  the  clavicle  to  the  upper  surface  of  the  first  costal 
cartilage. 

The  synovial  membranes  form  two  sacs  separated  by  the 
interarticular  cartilage. 

The  arteries  are  from  muscular  branch  of  suprascapular 
and  contiguous  muscular  branches; 

The  nerves,  from  descendens  noni. 

Acromioclavicular  articulation  {articulatio  acromio- 
clavieularis)  is  an  arthroidal  joint  formed  between  the  acromial 
extremity  of  the  clavicle  and  the  acromial  process  of  the  scapula. 
Its  ligaments  are : — 


1,  superor  acromioclavicular  ligaments;  2,  eoracoclavicular  liga- 
ments; 3,  coracoacromial  ligaments;  4,  transverse  ligament;  5,  cap- 
sular  ligament;    6,    coracohumeral    ligament;    7,    tendon    of   biceps. 

The  superior  acromioclavicular  (ligamentum  acromio- 
claviciUare)  connect  the  adjoining  parts  of  the  superior  surfaces 
of  the  clavicle  and  acromion  process; 

Inferior  acromioclavicular,  connecting  the  inferior  surfaces; 

Coracoclavicular  (lijamentum  coracoclaviculare)  consists  of 
two  parts : — 

Trapezoid  ( ligamen  I  h  m  trapezoideum) }  broad,  square, 
arises  from  upper  surface  of  coracoid  process,  and  is  inserted 
into  oblique  line  on  under  surface  of  clavicle;  and 

Conoid  {ligamentum  conoideum),  behind  and  internal, 
arises  from  base  of  coracoid  process,  and  is  inserted  into  conoid 

tubercle  on   under  side  of  clavicle  and  a  line   infernal  to  it. 

The  ligaments  surrounding  the  joint  form  a  capsule. 


116  HUMAN    ANATOMY. 

The  arteries  are  from  anterior  circumflex,  acromial  thora- 
cic and  suprascapular. 

The  nerves  are  anterior  circumflex  and  suprascapular. 

The  scapula  has,  also, 

The  coracoacromial  (ligamentum  coracoacromiale) ,  arising 
from  the  outer  border  of  the  coracoid  process  and  inserted  into 
.the  summit  of  the  acromion,  and 

Transverse  (lig amentum  transversum  scapula  superius),  a 
ligamentous  band  bridging  the  suprascapular  notch,  converting 
it  into  a  foramen  for  suprascapular  nerve. 

The  si-iouldee  joint  (articulatio  humeri)  is  an  enar- 
throdial  joint,  formed  above  by  the  glenoid  cavity  of  the  scapula 
and  below  by  the  head  of  the  humerus.  Its  ligaments  are : 
glenoid,  coracohumeral  and  capsular. 

The  glenoid  (labrum  glenoidale)  surrounds  the  edge,  deep- 
ens the  glenoid  cavity,  and  is  continuous  above  with  the  long 
head  of  the  biceps  tendon. 

The  capsular  ligament  (capsula  articularis) ,  extensive  and 
loose,  arises  above  it  from  circumference  of  glenoid  cavity  be- 
hind the  ligament,  is  attached  below  to  the  anatomical  neck  of 
humerus,  and  is  pierced  by  tendons  of  two  or  three  muscles. 

The  coracohumeral,  or  accesory  (ligamentum  coracoJiu- 
merale),  is  a  fibrous  band  which  extends  obliquely  downward 
and  outward  from  the  coracoid  process  to  the  anterior  part  of 
great  tuberosity,  strengthening  the  capsular  ligament. 

The  synovial  membrane  is  extensive  and  reflected  upon  the 
tendon  of  biceps,  which  is  inclosed  in  a  tubular  sheath  of  syno- 
vial membrane  (vagina  mucosa  intertubercularis) ,  and  upon  the 
infraspinatus,  and  subscapularis  muscles. 

Its  arteries  are  derived  from  the  subscapular,  suprascapular, 
dorsalis  scapulas,  anterior  and  posterior  circumflex; 

Its  nerves,  from  the  subscapular,  suprascapular  and  cir- 
cumflex. 

The 'elbow  joint  (articulatio  cubiti)  is  a  ginglymoid 
articulation  formed  above  by  the  lower  extremity  of  humerus, 
below  by  upper  extremities  of  ulna  and  radius.  Its  ligaments 
are  external  and  internal  lateral,  anterior  and  posterior  liga- 
ments. 

External  lateral  (ligamentum  collaterale  radiale)  arises 
from  external  condyle  of  humerus  and  is  inserted  into  outer 
margin  of  ulna.  Internal  lateral  (ligamentum  collaterale  ul- 
nare),  much  stronger,  consists  of  two  portions;  anterior  arises 
from  fore  part  of  internal  condyle  to  be  inserted  into  coronoid 


ARTICULATIONS    AXD    LIGAMENTS. 


Ill 


process,  and  posterior  from  back  part  of  condyle  to  inner  mar- 
gin of  olecranon. 

Anterior  ligament  arises  above  coronoid  fossa,  and  is 
inserted  into  coronoid  process  of  ulna  and  orbicular  ligament. 

Posterior  ligament,  attached  above  olecranon  fossa,  and 
below  to  olecranon  process  of  ulna.  The  anterior  and  posterior 
ligaments  become  continuous  with  the  lateral  to  encircle  the 
joint. 

The  arteries  are  derived  from   superior  and  inferior  pro- 


FlG.  64. 

1,  anterior  ligament:  2  and  2,  anterior  and  posterior  portions  of 
internal  lateral;  3,  orbicular  ligament;  4,  oblique;  5,  interosseous 
membrane. 

funda.    anaatomotiea   magna,    posterior   interosseous   recurrent, 
anterior  and   posterior  ulnar  recurrent  and   radial  recurrent. 

The  nerves,  from  median,  ulnar,  musculocutaneous  and 
musculospiral. 

Tilt;  RADIOULNAR  ARTICULATIONS    (articula I i<i  nul ioiilna ris  ) 

are  three:   the  superior,  middle  and  inferior. 

The  superior  radioulnar  (articulatio  radioulnar^  proxi- 
malie)  ie  a  diarthrosis  rotatoria,  formed  by  the  inner  side  of 
the  head  of  radius  and  lesser  sigmoid  cavity  of  ulna.  Its 
synovial  cavity  communicates  with  the  elbow  joint,  and   it    is 


118  HUMAN    ANATOMY. 

held  together  by  the  orbicular,  or  annular  ligament  (ligamen- 
tum annulare  radii),  attached  in  front  and  behind  to  the  lesser 
sigmoid  cavity  and  surrounding  the  head  of  radius.  Its  arteries 
and  nerves  are  the  same  as  for  elbow. 

The  middle  radioulnar  articulation  consists  of  the  oblique, 
or  round  ligament  (chorda  obliqua),  passing  from  tubercle  of 
ulna  to  below  tuberosity  of  radius,  and  the  interosseous  (mem- 
brana  interossea  antibrachii)  passing  between  the  bones,  deficient 
above  for  passage  of  posterior  interosseous  vessels,  and  perfo- 
rated below  for  anterior  vessels.  Its  arteries  are  from  anterior 
interosseous ;  its  nerves,  from  anterior  and  posterior  interosseous. 

Inferior  radioulnar  (articulatio  radioulnaris  distal  is)  con- 
sists of  anterior  and  posterior  radioulnar  ligaments,  passing 
from  one  to  the  other  in  front  and  back  of  wrist,  and  triangular 
interarticular  fibrocartilage  (discus  articularis) ,  interposed  be- 
tween head  of  ulna  and  cuneiform  bone,  and  binding  the  radius 
and  ulna  firmly  together.  Its  arteries  are  from  anterior  and 
posterior  interosseous  and  carpal;  its  nerves,  from  median  and 
posterior  interosseous. 

The  eadiocarpal  (articulatio  radio  car p  ea) ,  or  wrist  joint, 
is  a  condyloid  joint  consisting  of  an  elliptical  cavity  formed  by 
the  radius  and  triangular  cartilage,  into  which  fits  the  convex 
surfaces  of  the  scaphoid,  semilunar  and  cuneiform  below.  Its 
ligaments  are  external  and  internal  lateral,  anterior  and  pos- 
terior radiocarpal. 

External  lateral  (ligamentum  collaterale  carpi  radiate) 
passes  from  the  styloid  process  of  radius  to  the  scaphoid,  os 
magnum  and  trapezium. 

Internal  lateral  (ligamentum  collaterale  carpi  ulnare) 
passes  from  the  styloid  process  of  ulna  to  the  cuneiform,  pisi- 
form and  annular  ligament. 

The  anterior  radiocarpal,  or  volar  ligament  (ligamentum 
radiocarpeum  volare),  is  a  broad  membrane  attached  above  to 
the  anterior  margin  of  the  radius,  its  styloid  process  and  ulna, 
and  below  to  cuneiform,  semilunar,  scaphoid  and  os  magnum, 
strengthened  by  a  band  extending  from  styloid  process  of  ulna 
to  semilunar  and  cuneiform. 

The  posterior  radiocarpal,  or  dorsal  ligament  (ligamentum 
radiocarpeum  dorsale),  is  attached  to  dorsal  margin  of  radius, 
and  below  to  cuneiform,  semilunar  and  scaphoid.  The  anterior 
and  posterior  radiocarpal  belong  to  the  annular  ligament  {vide 
fascias). 

Its  arteries  are  the  anterior  and  posterior  carpal,  derived 


ARTICULATIONS    AM)    LIGAM  KNTS.  119 

from  the  radial  and  ulnar,  anterior  and  posterior  interosseus, 
and  ascending  branches  from  the  deep  palmar  arch. 

Its  nerves  are  derived  from  the  median,  ulnar  and  pos- 
terior interosseous. 

The  carpal  articulations  (articulatio  intercarpea)  are  ar- 
throdial,  and  consist  of  three  sets.  The  first  row  is  held  together 
by  two  palmar,  two  dorsal  and  two  interosseous;  the  second  row 
by  three  dorsal,  three  palmar  and  three  interosseous;  and  the 
two  rows  are  held  together  by  a  palmar,  dorsal,  internal  and 
external  lateral  ligament. 

First  bow. — The  palmar,  or  volar  (ligamenta  intercarpea 
volaria),  and  dorsal  ligaments  (ligamenta  intercarpea  dorsalia), 
connect  the  scaphoid  and  semilunar,  and  semilunar  and  cunei- 
form together  on  the  front  and  back. 

The  interosseous  (ligamenta  intercarpea  interossea)  con- 
nect the  semilunar  with  the  scaphoid  and  cuneiform. 

The  pisiform  bone  has  a  separate  capsular  ligament  and  an 
interosseous  ligament  connecting  it  to  the  fifth  metacarpal  bone 
and  cuneiform. 

Second  Eow. — The  palmar  (ligamenta  intercarpea  vol- 
aria),  and  dorsal  ligaments  (ligamenta  intercarpea  dorsalia), 
connect  the  trapezium  with  the  trapezoid,  and  the  os  magnum 
with  the  trapezoid  and  unciform,  on  the  front  and  back  of  the 
wrist. 

The  interosseus  (ligamenta  intercarpea  interossea)  connect 
the  adjacent  surfaces  of  the  trapezium  and  trapezoid,  and  the 
os  magnum  with  the  trapezoid  and  unciform. 

Two  Hows  Together, — The  palmar  (ligamenta  intercar- 
pea volaria)  and  dorsal  (ligamenta  intercarpea  dorsalia)  con- 
nect the  bones  of  the  first  with  the  second  rows  on  the  front  and 
back  of  the  wrist.  The  internal  lateral  passes  on  the  ulnar  side 
between  the  cuneiform  and  unciform.  The  external  lateral, 
stronger,  passes  on  the  radial  side  between  the  scaphoid  and 
trapezium. 

The  anterior  annular  ligament  (ligamenlum  carpi  trans- 
versum  )  contributes  strength  to  these  joints. 

The  arteries  are:  Carpal  of  anterior  interosseus,  anterior 
and  posterior  carpals  of  radial  and  ulnar,  carpal  of  deep  palmar 
arch,  Interosseous  recurrent,  and  terminal  branches  of  anterior 
and  posterior  interosseus. 

The   nerves   are    from    i linn,    ulnar   anil    posterior    inter- 

osseus. 

Till-;  CABFOMETACARPAL  ARTICULATIONS  (ar/iciihilioiii's  car- 
pomclticarpea')  are  each  arthrodial  joints,  held,  together  by  dor- 


120  HUMAN    ANATOMY. 

sal,  palmar,  interosseous  and  capsular  ligaments,  except  the 
thumb,  which  has  only  capsular. 

The  capsular  ligament  (capsula  articularis)  of  the  thumb 
surrounds  the  margins  of  the  articular  surfaces  of  the  first 
metacarpal  and  trapezium,  and  is  lined  by  a  separate  synovial 
sac. 

The  palmar,  or  volar  ligaments  (ligamenta  carpometa- 
carpea  volaria),  and  dorsal  carpometacarpal  (ligamenta  carpo- 
metacarpea  dorsalia) ,  connect  the  carpus  and  metacarpus  on 
the  palmar  and  dorsal  surface. 

The  interosseus  connect  the  adjoining  inferior  angles  of 
os  magnum  and  unciform  with  the  contiguous  surfaces,  fourth 
and  fifth  metacarpal  bones. 

The  synovial  membranes  of  the  wrist  consist  of  five  distinct 
sacs:  First,  membrana  sacciformis  lines  lower  end  of  ulna,  sig- 
moid cavity  of  radius  and  upper  surface  of  triangular  cartilage; 
second,  lower  surface  of  radius  and  cartilage  and  upper  surface 
of  first  row  of  carpus;  third,  between  margins  of  carpus  and 
carpometacarpal  joints;  fourth,  between  carpometacarpal  joint 
of  thumb ;  and  fifth,  between  pisiform  and  cuneiform. 

Intermetacarpal  Articulation. — The  bases  of  the  metacarpal 
bones,  except  the  thumb,  articulate  with  one  another  by  arthro- 
dial  joints,  lined  by  synovial  membrane  continuous  with  the 
carpal  sac  and  connected  together  by  palmar  [ligamenta  basium 
oss.  metacarp.  volaria),  dorsal  (ligamenta  basium  oss.  meta- 
carp. dorsalia),  and  interosseous  (ligamenta  basium  oss.  meta- 
carp. interossea)  ligaments.  The  digital  extremities  are  con- 
nected by  a  transverse  ligament  (lig amentum  capitulorum  oss. 
metacarpalium  transversum)  across  the  anterior  surface,  con- 
tinuous with  anterior  metacarpophalangeal  ligament. 

The  metacarpophalangeal  (articulationes  metacarpo- 
phalangeal) and  phalangeal  are  of  the  condyloid  variety,  like 
the  wrist  joint,  allowing  of  motion  in  every  direction  except 
laterally.  They  are  each  connected  by  one  anterior  palmar,  or 
vaginal  ligament  (glenoid  ligament  of  Cruveilhier,  ligamentum 
vaginale),  and  two  lateral,  or  collateral  ligaments  (ligamenta 
collateralia) ,  the  posterior  ligament  being  substituted  by  the 
extensor  tendon,  which  crosses  the  dorsum  of  the  joint. 

The  arteries  and  nerves  are  from  the  digitals. 

ARTICULATIONS    OF    THE    LOWER    EXTREMITY. 

The  hip  joint  (articulatio  coxa?)  is  a  true  enarthrodial 
articulation,  formed  above  by  deep  cup-like  cavity  of  acetabu- 


ARTICULATIONS    AND    LIGAMENTS.  121 

mm,  below  by  prominent  spherical  head  of  femur.  Its  liga- 
ments are  the  capsular,  iliofemoral,  teres,  cotyloid  and  trans- 
verse. 

The  capsular  ligament  (capsida  articularis) ,  dense  and 
strong,  is  attached  above  to  margin  of  acetabulum  and  cot- 
yloid ligament,  and  below  to  the  spiral  line  in  front  and  to 
the  neck  behind.  It  is  strengthened  by  several  accessory  bands, 
the  pubofemoral  (ligamentum  pubocapsulare),  iliotroehan- 
teric,  ischiocapsular  (ligamentum  iscliiocapsulare) ,  and  ilio- 
femoral (ligamentum  iliofe morale).  Of  these  the  latter  is  the 
most  important,  arising  above  from  anterior  inferior  spine,  and 
attached  below  to  spiral  line,  and  has  received  the  name  of 
Y -ligament  of  Bigelow. 

The  ligamentum  teres  {ligamentum  teres  femoris),  or 
round  ligament,  is  a  strong  triangular  band,  its  base  arising 
from  the  bottom  of  acetabulum  and  margins  of  cotyloid  notch 
externally,  its  apex  inserted  below  and  behind  center  of  head  of 
femur. 

The  cotyloid  ligament  (labrum  glenoidale)  encircles  and 
deepens  the  acetabulum,  and  at  the  inner  side,  under  the  name 
of  the  transverse  ligament  (ligamentum  transverswm  acetabuli), 
it  bridges  over  the  cotyloid  notch,  converting  it  into  a  foramen 
for  the  passage  of  nutrient  vessels  to  the  joint. 

There  are  numerous  bursa  about  the  joint,  with  one  of 
which,  beneath  the  iliopsoas  muscle,  the  synovial  membrane 
often  communicates. 

Its  in  levies  are  derived  from  the  sciatic,  internal  and  exter- 
nal circumflex,  obturator  and  gluteal. 

Its  nerves  are  derived  from  the  great  sciatic,  obturator. 
accessory  obturator  and  the  sacral  plexus. 

The  knee  . joint  (articulatio  genu)  is  a  ginglymoid  artic- 
ulation, formed  above  by  condyles  of  femur,  below  by  head  of 
tibia,  and  in  front  by  patella. 

It-  ligaments  are  divided  into  two  sets,  the  external,  con- 
sisting of  anterior,  posterior,  internal  lateral,  two  external 
laterals  and  capsular;  and  internal,  consisting  of  anterior, 
posterior,  two  semilunar  fibrocartilages,  transverse,  coronary, 
ligamentum  mucosum  and  ligaments  alaria.  Its  joint  surface 
i-  the  most  extensive  in  the  body. 

External  Set. — Anterior,  or  ligamentum  patella,  is  the 
tendinous  portion  of  extensors  of  thigh  between  patella  and 
tul.enle  of  tibia.     The  posterior   (ligamentum  popliteum  obli- 

ijiinm).  or  ligamentum,  poslirum  Winsloirii,  derived  principally 
from   the  tendon  of  semimembranosus,  arises    from   inner  tuber- 


122  HUMAN    ANATOMY. 

osity  of  tibia,  passes  upward  and  outward  to  be  inserted  into 
external  condyle  of  femur. 

The  internal  lateral  (ligamentum  collaterale  tibiale)  is  a 
flat  and  broad  ligament  arising  from  back  part  of  inner  condyle 
of  femur,  descends  forward  to  be  inserted  into  inner  tuberosity 
of  tibia,  covering  in  its  course  the  inferior  internal  articular 
artery  and  nerve,  part  of  tendon  of  semimembranosus,  and 
attaching  itself  to  the  internal  semilunar  fibrocartilflge, 

The  long  external  lateral  ligament  (ligamentum  collaterale 
fibular e),  round  and  strong,  arises  from  tuberosity  on  outer  part 
of  external  condyle,  and  descends  forward  to  the'  head  of  fibula. 
The  short  external  lateral  ligament  {ligamentum  laterale  exter- 
num breve  sen  posticum)  is  an  accessory,  not  very  constant, 
band,  descending  posteriorly  to  the  preceding. 

The  capsular  ligament  (capsula  articularis)  fdls  up  the 
intervals  between  the  preceding  ligaments,  and  is  strengthened 
by  bands  from  fascia  lata,  vasti,  crureus,  semimembranosus, 
biceps  and  sartorius  tendons. 

Internal  Set. — Crucial  ligaments  (ligamenta  cruciata  genu) 
are  two  strong,  short,  interosseous,  crossing  each  other  from 
before  backward.  The  anterior,  or  external  (ligamentum  cru- 
ciatum  anterius),  arises  from  inner  posterior  part  of  condyle 
of  femur,  and  descends  forward  and  inward  to  be  inserted  into 
front  of  spine  of  tibia  and  internal  semilunar  cartilage. 

The  posterior,  or  internal  (ligamentum  cruciatum  pos- 
terius),  arises  from  outer  fore  part  of  inner  condyle  of  femur, 
descends  downward,  backward  and  outward  to  spine  of  tibia. 

The  semilunar  fibro 'cartilages  (menisic)  consist  of  two  cres- 
centic  laminae  of  interarticular  cartilage,  resting  upon  the  upper 
articular  surface  of  tibia,  which  serve  to  deepen  its  surface. 

The  internal  (meniscus  medialis)  is  attached  by  its  inner 
border  to  internal  lateral  ligament  and  to  head  of  tibia  by 
coronary  ligaments,  its  extremities  attached  in  front  of  anterior 
crucial  ligament  and  behind  the  spine. 

The  external  (meniscus  lateralis),  more  circular,  is  con- 
nected to  edge  of  tibial  head  by  coronary  ligaments,  its  extremi- 
ties being  inserted  behind  and  in  front  of  the  tibial  spine. 

In  other  words,  the  ends  of  the  semilunar  cartilages  are  all, 
except  the  anterior  end  of  internal,  attached  to  the  tibia  between 
the  crucial  ligaments. 

A  band  of  fibers  passing  from  the  anterior  margin  of  exter- 
nal cartilage  to  the  internal  has  received  the  name  of  transverse 
ligament  (ligamentum  transversum  genu). 


ARTICULATION    AND    LIGAMENTS. 


123 


The  knee  is  lined  by  the  most  extensive  synovial  membrane 
in  the  body,  covering  both  surfaces  throughout  and  extending 
up  between  quadriceps  tendon  and  surface  of  femur. 

Below  the  patella  in  front  is  a  duplicative  of  synovial  mem- 
brane, inclosing  some  adipose  tissue,  which  has  received  the 
name  of  ligamentum  mucosum  (plica  synovialis  patellaris) ,  and 
extending  from  it  are  two  fringes — the  ligamenta  alaria  (plicce 
alares). 

On  either  side  in  the  popliteal  space  behind  are  bursa?, 
which  often  communicate  with  the  joint. 

There  are  also  bursas  over  the  patella?,  above  and  beneath 


Fig.  65. 

2,  anterior  crucial  ligament;  3, 
posterior  crucial  ligament;  4,  trans- 
verse ligament;  6,  7,  internal  and  ex- 
ternal semilunar  cartilages;  8,  liga- 
menta patellae;  9,  bursa  patellae;  10, 
anterior  superior  tibiofibular  liga- 
ment. 


Fig.  66. 

2,  quadriceps  extensor;  3,  patella; 
4,  ligamentum  patellae;  6.  bursa;  7, 
8,  9,  synovial  membrane  of  knee  joint; 
10,   anterior  crucial   ligament. 


the  ligamentum  patellae,  and  between  the  inner  hamstring  and 
head  of  tibia. 

The  arteries  of  the  knee  joint  are  derived  from  the  anasto- 
motic magna,  the  articular  branches  of  the  popliteal  (five),  and 
the  recurrent  branch  of  the  anterior  tibial. 

[tfl  nerves  are  derived  from  the  anterior  crural,  obturator, 

trial  and  internal  popliteal  nerves. 

The  TIBIOFIBULAR  ARTICULATIONS  (articulatio  tibiofibu~ 
la/ris)  are  three— superior,  middle  ami  inferior.  The  superior 
ie  an  arthrodiai  joint  between  fibular  head  and  outer  tuberosity 
of  tibia,  and  consists  of  anterior  superior  and  posterior  superior 


124  HUMAN    ANATOMY. 

ligaments1  stretching  on  either  side  of  the  outer  tuberosity, 
downward  and  backward,  to  the  head  of  the  fibula.  The  arteries 
are  same  as  the  knee;  the  nerves,  from,  external  popliteal. 

The  middle  consists  of  an  interosseous  membrane  (mem- 
brana  interossea  cruris)  between  the  bones,  connecting-  them 
firmly  together,  deficient  above,  for  passage  forward  of  anterior 
tibial  artery  and  below  for  anterior  peroneal  vessels. 

The  inferior  (syndesmosis  tibiofibularis)  is  an  arthrodial 
joint  between  contiguous  inferior  surfaces  of  tibia  and  fibula, 
•and  consists  of  four:  the  interosseus,  continuous  with  that 
above;  the  anterior,  inferior  tibiofibular  (ligamentum  malleoli 
lateralis  anterius),  extending  downward  and  outward  between 
tibia  and  fibula  in  front;  the  posterior  inferior  tibiofibular  (liga- 
mentum malleoli  lateralis  posterius),  occupying  a  similar  posi- 
tion behind;  and  the  transverse,  a  long  narrow  band,  passing 
between  external  malleolus  and  tibia.  The  synovial  membrane 
is  continuous  with  that  of  ankle-joint.  The  arteries  and  nerves 
are  the  same  as  those  to  the  ankle. 

The  ankle-joint  (articulatio  talocruralis)  is  a  gingly- 
moid  articulation,  formed  between  the  lower  extremity  and 
malleolus  of  tibia  on  the  inner  side,  the  malleolus  of  the  fibula 
on  the  outer  side,  and  the  astragalus  below.  Its  ligaments  are 
anterior,  posterior,  external  and  internal  lateral. 

The  anterior  tibiotarsal  ligament  (ligamentum  talotibiale 
anterius)  consists  of  a  broad  set  of  irregular  fibers,  attached 
above  to  lower  margin  of  tibia,  below  to  astragalus.  The  pos- 
terior tibiotarsal  ligament  (ligamentum  talotibiale  posterius) 
passes  transversely  between  back  part  of  tibia  and  astragalus. 

The  internal  lateral,  or  deltoid  (ligamentum  calcaneotibial 
or  ligamentum  deltoideum),  has  two  layers — the  superficial 
triangular,  its  apex  arising  from  malleolus,  its  base  spread  out 
from  before  backward  to  be  attached  to  scaphoid  and  inferior 
calcaneoscaphoid  ligament,  the  sustentaculum,  and  inner  side  of 
astragalus;  and  the  deep,  a  short,  round  cord  passing  from 
internal  malleolus  to  astragalus. 

The  external  lateral  ligament  (ligamenta  talofibularia  et 
calcaneofibulare)  consists  of  three  distinct  fasciculi,  anterior 
(ligamentum  talofibular ~e  anterius),  middle  (ligamentum  cal- 
caneofibidare) ,  and  posterior  (ligamentum  talofibulare  pos- 
terius), arising  from  near  summit  of  external  malleolus,  and 


1  The  new  anatomical  nomenclature  (BNA)  [inserted  through- 
out the  present  edition  of  this  volume]  considers  the  anterior  superior 
and  the  posterior  superior  tibiofibular  ligaments  as  one  ligament  [liga- 
mentum capituli  fibulas). 


ARTICULATIONS    AND    LIGAMENTS.  125 

being  inserted  respectively  into  the  front  of  astragalus,  the  outer 
surface  of  os  calcis,  and  the  back1  of  astragalus. 

The  arteries  of  the  ankle-joint  are  derived  from  the  malleo- 
lar branches  of  the  peroneal  and  anterior  tibial. 

Its  nerves  are  branches  of  the  anterior  and  posterior  tibial 
nerves. 

The  articulations  of  the  tarsal  bones  (articulationes 
intertarsece)  consist  of  those  of  the  first  row,  those  of  the  second 
row.  and  of  the  two  rows  with  each  other. 

First  Eow. — The  astragalus  articulates  with  the  calcaneum 
by  two  distinct  surfaces  separated  by  the  interosseous  groove, 
and  firmly  connected  by  the  external  (ligament um  talocalcaneum 
laterale),  and  posterior  (ligamentum  talocalcaneum  posterius) 
calcaneoastragaloid  ligaments,  and  the  interosseus  (ligamentum 
talocalcaneum  interossmm) .  The  external  calcaneoastragaloid 
ligament  passes  vertically  downward  from  the  outer  surface  of 
astragalus  to  outer  surface  of  calcaneum.  The  posterior  is  a 
short,  narrow,  oblique  band  connecting  the  posterior  border  of 
astragalus  to  the  os  calcis. 

The  interosseus  (ligamentum  talocalcaneum  interosseum) 
is  a  strong,  short  ligament  passing  vertically  and  obliquely 
downward  between  the  two  bones,  the  principal  bond  of  union. 
'  The  arteries  of  the  first  row  are  tarsal  from  dorsalis  pedis, 
external  malleolar  from  anterior  tibial,  and  branches  of  peroneal 
from  posterior  tibial. 

Nerves,  from  posterior  tibial,  or  plantar. 

The  second  eow  is  firmly  held  together  by  dorsal,  plan- 
tar and  interosseous  ligaments.  The  two  former  unite  the  dor- 
sal and  plantar  surfaces  and  the  interosseous,  four  strong  bauds 
connect  the  scaphoid  and  cuboid  (articulatio  cubonavicularis) , 
the  internal  and  middle,  the  middle  and  external  cuneiform, 
and  the  external  cuneiform  and  cuboid. 

The  arteries  of  the  second  row  are  from  plantars  and  meta- 
tarsals. Nerves,  from  anterior  tibial,  and  internal  and  external 
divisions  of  posterior  tibial  nerves. 

The  two  bows  of  the  taesus  (articulationes  intertarseos) 
are  connected  with  each  other  by  three  sets  of  ligaments,  first 
between  os  calcis  and  cuboid,  consisting  of  superior  (ligamen- 
tum calcaaieocuboideum  dorsale)  and  internal  calcaneocuboid 
[pars  oalcaneocuboidea  ligamenti  bifurcati),  long  (ligamentum 
plan  fare  longum) ,  and  short  calcaneocuboid  (ligamentum  cal- 
caneocuboid earn  plantare)  ;  second,  between  os  calcis  and  sca- 
phoid, consisting  of  superior  or  external,  or  calcaneonavicular 
(pars    calcaneonavicularis    ligamenti    bifurcati),    and    inferior 


126  HUMAN    ANATOMY. 

calcaneoscaphoid,  or  internal  or  calcaneonavicular  (ligamentum 
calcaneonavicular 'e  plantare)  ;  and  third,  between  astragalus  and 
scaphoid  (artimlatio  talonavicularis) ,  consisting  of  a  single 
superior  astragaloscaphoid  ligament,  a  band  passing  from  neck 
of  astragalus  to  upper  surface  of  scaphoid. 

Calcaneocuboid, — The  superior  (lig amentum  calcaneocu- 
boideum  dorsale)  passes  between  dorsal  surfaces  of  os  calcis  and 
cuboid.  The  internal  (pars  calcaneocuboid  ea  ligamenti  bifur- 
cati)  passing  from  os  calcis  to  inner  side  of  cuboid,  is  one  of 
the  main  bonds  of  union  between  the  two  rows  of  tarsus. 

The  inferior  firmly  connects  the  bones  below,  the  lig  amen- 
tum longce  plantce  passing  from  os  calcis  forward  to  the  plantar 
surface  of  the  cuboid,  and  sending  fibers  forward  to  bases  of 
second,  third  and  fourth  metatarsal  bones;  the  lig  amentum 
breve  plantce  passing  from  fore  and  under  surface  of  os  calcis  to 
under  surface  of  cuboid.  The  two  preceding  are  important  in 
preserving  the  arch  of  the  foot. 

The  superior  and  inferior  calcaneoscaphoid  pass  above  and 
below  these  bones,  firmly  connecting  them. 

The  arteries  of  the  mediotarsal  joints  are  derived  from  the 
anterior  tibial,  tarsal,  metatarsal,  or  external  plantar. 

Nerves,  from  external  branch  of  anterior  tibial. 

The  tarsometatarsal  articulations  (articulationes  tar- 
sometatarsew)  are  firmly  held  together  by  dorsal  (lig amenta 
tarsometatarsea  dorsalia)  and  plantar  (Kgamenta  tarsometa- 
tarsea  plantaria)  ligaments,  and  connected  with  one  another 
by  interosseous  bands  (ligamenta  cuneometatarsea  interossea), 
three  in  number,  passing  between  internal  cuneiform  and  second 
metatarsal  bone,  external  cuneiform  and  second  metatarsal,  and 
external  cuneiform  and  third  metatarsal. 

The  arteries  are  from  metatarsal,  dorsalis  pedis,  and  deep 
plantar  arch; 

The  nerves  are  from  anterior  tibial  and  external  plantars. 

Intermetatarsal  Articulations-  (articulationes  inler- 
metatarsew) . — The  bases  of  all  except  the  first  are  connected 
by  dorsal  (ligamenta  basium  [oss.  metatars.~\  dorsalia),  plantar 
(ligamentum  basium  [oss.  meiatars.']  plantaria),  and  the  inter- 
osseous ligaments  (ligamenta  basium  [oss.  metatars.']  interos-' 
sea),  and  the  distal  extremities  are  connected  by  the  transverse 
metatarsal  ligament. 

The  synovial  membranes  concerned  in  these  articulations 
are  six:  (1)  between  the  calcaneoastragaloid  articulation,  pos- 
terior to  interosseous  membrane;  (2)  anterior  calcaneoastraga- 


ARTICULATIONS    AND    LIGAMENTS.  127 

loid  and  astragaloscaphoid ;  (3)  calcaneocuboid;  (-1)  between 
the  middle  and  the  external  cuneiform,  scaphoid  and  three  cunei- 
form, middle  and  external  cuneiform,  and  second  and  third 
metatarsal,  and  between  the  cuboid  and  the  external  cuneiform 
and  the  scaphoid ;  ( 5 )  between  the  internal  cuneiform  and  first 
metatarsal;  and  (6)  between  the  cuboid  and  the  fourth  and 
fifth  metatarsal. 

The  metatarsophalangeal  articulations  (articula- 
tion es  metatarsophalangeal)  are  each  connected  by  two  lateral 
(ligamcnta  collateralia),  and  a  plantar  ligament  or  glenoid 
ligaments  of  Cruveilhier  (ligamenta  accessoria  plantaria)  and 
the  phalangeal  articulations  are  the  same,  the  extensor  tendons 
acting  as  dorsal  ligaments.  They  resemble  in  every  respect  the 
articulations  in  the  hand  (vide  Hand). 


THE  MUSCULAR  SYSTEM. 


The  muscles  constitute  45  per  cent,  of  the  body  weight  and 
are  the  active  agents  of  locomotion. 

They  consist  of  two  kinds — -the  non-striated  or  involun- 
tary, and  the  striated,  or  voluntary.  The  latter,  being  usually 
under  the  control  of  the  will  (the  heart  being'  a  notable  excep- 
tion), have  also  received  the  name  of  voluntary,  and  the  former, 
not  under  the  control  of  the  will,  involuntary. 

Microscopically,  their  structure  is  as  follows: — 

Non-striated  muscular  tissue  is  made  up  of  elongated,  con- 
tractile, nucleated  fiber-cells.  They  consist  of  minute  fibers  in 
bundles,  inclosed  in  extremely  delicate  sheaths  of  connective 
tissue. 

They  are  held  together  by  an  albuminous  cement  and  col- 
lected by  connective  tissue  into  groups  or  masses  one-tenth  to 
one  five-hundredth  of  an  inch  in  length. 

Non-striated  muscular  tissue  is  highly  vascular  and  is  sup- 
plied with  nerves  from  the  sympathetic. 

Striated  muscular  tissue  is  made  up  of  spindle-shaped  fibers 
of  from  one  and  a  half  to  two  inches  in  length  and  one-two- 
hundredth  to  one-six-hundredth  of  an  inch  in  diameter.  They 
are  held  together  in  bundles  by  the  endomysium,  a  delicate  fibro- 
connective  tissue.  These  bundles  are  collected  into  groups  by 
the  perimysium,  a  stronger  connective-tissue  band,  forming  the 
fasciculi  of  the  fully  formed  muscle.  Striated  muscular  tissue 
is  also  highly  vascular. 

The  parts  of  an  individual  fiber  are — first,  the  sarcolemma, 
a  very  delicate,  transparent,  elastic  sheath;  second,  the  mem- 
branes of  Krause,  which  appear  as  dark  lines  stretching  across 
the  fiber  at  regular  intervals,  forming  the  third,  or  the  com- 
partments of  Krause,  which  contain  the  muscular  substance. 
The  latter  contain  the  multinucleated  muscle-cells. 

The  striated  muscular  fibers  of  the  heart  differ  somewhat 
from  the  preceding,  being  branched,  and  dividing  and  subdivid- 
ing longitudinally  to  form  an  intricate  network. 

The  muscles  are  connected  to  cartilages,  ligaments,  bones 
and  skin,  either  directly  or  by  aponeuroses  or  tendons. 

(128) 


THE    MUSCULAR    SYSTEM.  129 

Aponeuroses  are  dense,  white,  fibrous  membranes,  serving 
to  connect  the  muscles  with  the  structures  to  be  acted  upon. 

Tendons  are  white,  fibrous,  glistening!  cords.  They  are 
composed  of  white,  fibrous  tissue,  arranged  into  bands  or 
bundles.  They  are  attached  to  the  perichondrium,  periosteum, 
ligaments  and  subcutaneous  tissue  by  a  mutual  interlacement 
of  fibers. 

Classification. — Muscles  are  classified  according  to  region 
of  the  body,  their  physiological  action,  or  from  their  embryo- 
logical  development.  The  former  arrangement  is  retained  here 
for  practical  purposes. 

Names  of  Muscles. — They  have  received  their  names: — 

1.  From  the  arrangement  of  their  fibers  they  are  designated 
radiated,  penniform,  bipenniform,  etc. 

2.  From  their  uses  they  are  called  extensors,  adductors,  etc. 

3.  From   their  direction,   oblique,   rectus,   transversalis,  etc. 

4.  From  the  number  of  insertions,  as  triceps,  biceps,  etc. 

5.  From  their  form,  as  rhomboid,  deltoid,  etc. 

6.  From  their  attachment,  as  oceipitofrontalis,  sternohyoid,  etc. 

The  origin  refers  to  the  fixed  extremity,  or  head  (caput)  ; 
the  insertion,  to  the  movable  point. 

Muscles  of  the  Head. 

cranial  region. 

OcciPiTOFitoxTALis  (m.  epicra nius) . — Origin,  by  two  bel- 
lies, one  from  outer  two-thirds  of  superior  curved  line  of  the 
occipital  bone  and  base  of  the  mastoid  process  of  the  temporal, 
the  other  from  corrugator  supercilii,  orbicularis  palpebrarum 
and  pyramidalis  nasi  fibers;  insertion,  into  fibrous  aponeurosis 
covering  the  vertex  of  the  skull ;  action,  raises  the  eyebrows  and 
used  chiefly  as  a  muscle  of  facial  expression;  nerves,  supraor- 
bital, small  occipital,  facial  and  posterior  auricular  branch  of 
facial. 

AURICULAR    REGION. 

Attollens  Aurbm  (m.  auricularis  superior). — Origin,  from 
aponeurosis  of  occipitof frontalis \  insertion,  into  the  surface  of 
the  pinna;  action,  raises  the  ear;  nerve,  occipitalis  minor. 

Attrahens  Aurem  (m.  auricularis  anterior). — Origin, 
from  edge  of  oceipitofrontalis  aponeurosis;  insertion,  into  an- 
terior part  of  helix;  action,  draws  the  ear  upward  and  forward; 
nerve,  facial. 

I*i -'i  B  \  it  ia's  Aum.nt  (ra.  auric uh ris  posterior). — Origin, 
from    mastoid    portion   of   temporal    bone;   insertion,   info   lower 


130  HUMAN    ANATOMY. 

part  of  concha;  action,  draws  the  ear  backward;  nerve,  posterior 
auricular  branch  of  facial. 

PALPEBRAL    REGION. 

Orbicularis  Palpebrarum  (m.  orbicularis-  oculi). — Origin, 
from  nasal  process  of  superior  maxilla,  internal  angular  process 
of  frontal,  and  from  front  and  sides  of  tendo  palpebrarum; 
insertion,  into  skin  of  the  cheek,  eyelids,  forehead  and  temple, 
blending  with  the  corrugator  supercilii  and  the  occipitofron- 
talis;  action,  sphincter  of  the  eyelids;  nerve,  facial. 

Tendo  Palpebrarum  (Tendo  Oculi),  or  internal  tarsal 
ligament  (ligamentum  palpebrale  mediate). — Origin,  nasal  proc- 
ess of  superior  maxilla ;  insertion,  inner  part  of  tarsal  cartilage. 

Corrugator  Supercilii. — Origin,  superciliary  ridge ;  inser- 
tion, into  orbicularis  about  the  middle  of  the  orbital  arch; 
action,  draws  eyebrows  inward  and  downward  and  wrinkles  the 
forehead;  nerve,  facial. 

Tensor  Tarsi,  or  Horner's  muscle  (pars  lacrimalis  of  the 
orbicularis  palpebrarum). — Origin,  from  crest  and  orbital  sur- 
face of  lachrymal  gland;  insertion,  into  tarsal  cartilages  near 
the  puncta  lachr}mialia ;  action,  draws  the  lachrymal  canals 
inward  and  against  the  globe  of  the  eye;  nerve,  facial. 

ORBITAL    REGION. 

Levator  Palpebr^:  Superioris. — Origin,  from  lesser  wing 
of  the  sphenoid,  near  the  optic  foramen ;  insertion,  superior  bor- 
der of  tarsal  cartilage;  action,  elevates  the  upper  eyelid;  nerve, 
third  cranial,  or  motor  oculi. 

Pectus  Superior  (m.  rectus  superior). — Origin,  sheath  of 
the  optic  nerve  and  upper  margin  of  optic  foramen;  insertion, 
into  upper  surface  of  sclerotic  coat;  action,  rotates  the  eyeball 
upward ;  nerve,  third  cranial. 

Pectus  Inferior  (m.  rectus  inferior). — Origin,  from  lower 
and  inferior  part  of  optic  foramen  (ligament  of  Zinn)  ;  inser- 
tion, into  lower  surface  of  sclerotic;  action,  rotates  the  eyeball 
downward;  nerve,  third  cranial. 

Rectus  Internus. — Origin,  same  as  rectus  inferior;  inser- 
tion, into  inner  surface  of  sclerotic;  action,  rotates  the  eyeball 
inward;  nerve,  third  cranial. 

Pectus  Externus  (m.  rectus  lateralis). — Origin,  by  two 
heads — lower  from  ligament  of  Zinn  and  lower  margin  of 
sphenoidal  fissure,  upper  from  outer  margin  of  optic  foramen; 
insertion,  into  outer  surface  of  sclerotic;  nerve,  abducens,  or 


THE  MUSCULAE  SYSTEM.  131 

sixth  cranial.  Passing  between  the  two  heads  are  the  ophthal- 
mic vein,  the  third,  nasal  branch  of  fifth,  and  sixth  nerves. 

Superior  Oblique  (m.  obliquus  superior). — Origin,  from 
inner  margin  of  optic  foramen :  its  tendon  passes  through  a 
pulley  near  the  internal  angular  process  of  the  frontal  bone; 
insertion,  into  sclerotic,  between  external  and  superior  recti, 
midway  between  entrance  of  optic  nerve  and  the  cornea;  action, 
rotates  the  eyeball  on  its  axis;  nerve,  fourth,  or  pathetieus. 

Inferior  Oblique  (m.  obliquus  inferior). — Origin,  orbital 
plate  of  superior  maxilla ;  insertion,  near  that  of  superior 
oblique,  between  external  and  superior  recti;  action,  rotates  the 
eyeball  on  its  axis;  nerve,  third  cranial. 

NASAL    REGION. 

Pyramidalis  Nasi  or  Procerus. — Origin,  from  the  occipi- 
tofrontalis;  insertion,  into  the  compressor  nasi;  action,  lowers 
the  inner  angle  of  the  eyebrows ;  nerve,  facial. 

Levator  Labii  Supebioris  Al.eque  Xasi. — Origin,  nasal 
process  of  superior  maxilla;  insertion,  the  ala  of  the  nose  and 
upper  lip.  blending  with  the  levator  labii  oris  proprius  and 
orbicularis ;  action,  dilates  the  nostril  and  elevates  the  upper 
lip;  nerve,  facial. 

Dilator  Naris  Posterior. — Origin,  nasal  notch,  of  su- 
perior maxilla;  insertion,  into  skin  at  the  margin  of  the  nostril. 

Dilator  Naris  Anterior. — Origin,  from  cartilage  of  the 
ala;  insertion,  into  the  skin  of  nose;  action,  dilates  the  nostrils; 
nerve,  facial. 

Compressor  Nasi. — Origin,  superior  maxilla,  near  the 
incisive  fossa;  insertion,  into  iibrocartilage  of  the  nose,  con- 
tinuous with  the  pyramidalis  nasi  aponeurosis  and  its  fellow; 
action,  dilates  the  nostril;  nerve,  facial. 

Compressor  Nabium  Minor. — Origin,,  from  alar  cartilage; 
insertion,  into  the  skin  of  the  end  of  the  nose;  action,  dilates 
the  nostril ;  nerve,  facial. 

Depressor  Ai.j.  Nasi  (depressor  septi\. — Origin,  incisive 
fossa  of  superior  maxilla;  insertion,  into  the  ala  of  the  nose; 
ii'lion.  contracts  the  nostril;  nerve,  facial. 

maxillary   region. 

Levator  Labii  Si  perIobis  (proprius). — Origin,  above  in- 
fraorbital foramen  to  malar  and  superior  maxilla;  insertion, 
into  the  npper  lip;  action,  elevates  the  upper  lip;  nerve,  facial. 


132  HUMAN    ANATOMY. 

Levator  Anguli  Oris  (m.  caninus). — Origin,  from  canine 
fossa;  insertion,  into  the  angle  of  the  mouth,  blending  with  the 
depressor  anguli  oris,  orbicularis,  and  zygomatici;  action,  draws 
the  angle  inward  and  raises  it;  nerve,  facial. 

Zygomaticus  Major  (m.  zygomaticus). — Origin,  from 
malar  bone;  insertion,  into  angle  of  mouth,  blending  with 
depressor  anguli  oris  and  orbicularis. 

Zygomaticus  Minor. — Origin,  from  malar  bone;  inser- 
tion, at  the  angle  of  the  mouth,  blending  with  the  levator 
superioris;  action,  draws  the  lip.  outward  and  upward;  nerve, 
facial. 

Levator  Labii  Inferioris  (m.  mentalis). — Origin,  from 
incisive  fossa  of  lower  jaw;  insertion,  into  the  skin  of  the  chin; 
action,  raises  the  lower  lip;  nerve,  facial. 

Depressor  Labii  Inferioris,  or  quadratus  menti  (m. 
quadratus  labii  inferioris). — Origin,  from  external  oblique  line 
of  lower  jaw;  insertion,  into  skin  of  lower  lip^  blending  with 
its  fellow  and  the  orbicularis;  action,  lowers  the  angle  of  the 
mouth;  nerve,  facial. 

Depressor  Anguli  Oris,  or  triangularis  menti  (m.  trian- 
gularis).— Origin,  external  oblique  line  of  lower  jaw;  insertion, 
into  the  angle  of  the  mouth,  continuous  with  the  orbicularis  and 
risorius  at  its  insertion  and  the  platysma  at  its  origin;  action, 
depresses  the  angle  of  the  mouth ;  nerve,  facial. 

Orbicularis  Oris. — Origin,  by  accessory  fibers  (accessorii 
orbicularis  superioris  and  inferioris  and  nasolabials),  from 
superior  and  inferior  maxillary  borders  and  nasal  septum ;  inser- 
tion, into  the  buccinator  and  adjoining  muscles,  forming  the 
sphincter  of  the  mouth ;  action,  closes  the  lips ;  nerve,  facial. 

Buccinator. — Origin,  from  pterygomaxillary  ligament  and 
the  posterior  alveolar  processes  of  the  upper  and  lower  jaw; 
insertion,  into  orbicularis  oris;  action,  compresses  and  contracts 
the  cheeks;  nerves,  facial  and  buccal  branch  of  the  inferior 
maxillary  nerve. 

EisORius  (m.  risorius)  (Santorini). — Otigin,  from  fascia 
of  masseter  muscle;  insertion,  at  angle  of  the  mouth;  action, 
draws  back  the  angles  of  the  mouth, — the  "smiling"  muscle; 
nerve,  facial. 

Masseter:  Superficial  Portion. — Origin,  inner  surface 
of  zygoma  and  malar  process  of  superior  maxilla ;  insertion,  into 
the  ramus  and  angle  of  the  lower  jaw. 

Deep  Portion. — Origin,  posterior  border  and  inner  sur- 
face of  the  zygoma;  insertion,  into  the  ramus  and  coronoid 
processi  of  the  jaw ;  action,  raises  the  lower  jaw,  and  the  super- 


THE    MUSCULAR    S  VST  KM.  133 

ficial  portion  assists  in  drawing  it  forward;  nerve,  inferior 
maxillary. 

Temporal  (m.  temporalis). — Origin,  from  the  temporal 
fascia  and  the  temporal  fossa;  insertion,  into  the  coronoid 
process  of  the  lower  jaw;  action,  raises  and  draws  backward  the 
lower  jaw;  nerve,  inferior  maxillary. 

Internal  Pterygoid  (m.  pterygoideus  internm). — Origin, 
from  pterygoid  fossa  and  the  tuberosity  of  the  palate-bone; 
insertion,  into  the  inner  side  of  the  ramus  and  angle  of  the 
lower  jaw;  action,  draws  forward  and  raises  the  lower  jaw;  the 
accessory  triturating  muscle  of  mastication;  nerve,  inferior 
maxillary. 

External  Pterygoid (m.  pterygoideus  externus). — Origin, 
by  two  heads — the  lower  from  the  tuberosities  of  the  palate  and 
superior  maxilla  and  from  the  external  pterygoid  plate,  the 
upper  from  the  pterygoid  ridge  on  the  greater  wing  of  the 
sphenoid;  insertion,  into  the  front  of  the  neck  of  the  lower  jaw 
and  inner  side  of  interarticular  cartilage;  action,  draws  the 
jaw  forward;  triturating  muscle  of  mastication;  nerve,  inferior 
maxillary. 

Muscles  of  the  Ear  (vide  Ear). 

Muscles  of  the  Neck. 

superficial   cervical  region. 

Platysma  Myoides  (m.  platysma). — Origin,  from  the 
deep  fascia  over  the  trapezius,  deltoid,  and  pectoral  muscles, 
and  from  the  clavicle  and  acromion;  insertion,  into  the  lower 
jaw  and  skin  of  the  face;  action,  wrinkles  the  skin  of  the  neck 
and  protects  the  air-passages  and  blood-vessels  from  external 
pressure. — rudimentary  in  man;  nerves,  branch  of  superficial 
cervical  plexus  and  the  facial. 

Stei;xocleidomastoid(  m.  sternocleidomastoideus) . — Origin, 
by  two  heads — sternal  portion  from  the  fore  and  upper  part  of 
the  manubrium  sterni,  the  clavicular  portion  from  the  inner 
third  of  the  upper  border  of  the  clavicle,  leaving  a  triangular 
interval;  msertwrij  into  t he  mastoid  process  and  outer  two- 
thirds  of  the  superior  curved  line  of  the  occipital  bone;  action, 
rotates  and  depresses  the  head;  nerves,  spinal  accessory  and 
branches  of  the  cervical  plexus. 

• 

infrahyoid  region. 

Sternohyoid  (m.  sternohyoideus) . — Origin,  from  upper 
and  back  part  of  the  manubrium  sterni  and  inner  extremity  of 


134  HUMAN    ANATOMY. 

the  clavicle;  insertion,  into  the  lower  border  of  the  os  hyoides; 
action,  depresses  the  hyoid  bone;  nerve,  branch  from  the  loop  of 
communication  between  the  deseendens  and  communicans  noni. 

Sternothyroid  (m.  sternothyroideus) . — Origin,  posterior 
surface  of  manubrium  sterni;  insertion,  into  oblique  line  of  the 
surface  of  the  thyroid  cartilage;  action,  depresses  the  larynx; 
nerve,  branch  from  the  communicating  loop  above. 

Thyrohyoid  (m.  tliyreohyoideus) . — Origin,  from  the  ob- 
lique line  on  the  surface  of  the  thyroid  cartilage ;  insertion,  into 
the  greater  cornu  and  body  of  the  hyoid  bone;  action,  elevates 
the  larynx;  nerve,,  hypoglossal. 

Omohyoid  (m.  omohyoideus). — Origin,  from  the  upper 
border  rv£  the  scapula  and  the  transverse  ligament ;  insertion, 
into  the  jwer  border  of  the  os  hyoides;  its  center  is  tendinous 
and  bound  clown  to  the  cartilage  of  the  first  rib  by  a  process  of 
the  deep  cervical  fascia;  action,  depresses  the  hyoid  bone  and 
draws  it  backward;  nerve,  from  the  communicating  loop  above. 

SUPRAHYOID    REGION. 

Digastric  (m.  digastricus) . — Origin,  by  two  bellies — pos- 
terior from  digastric  groove'  of  mastoid  process  of  the  temporal 
bone,  anterior  from  a  depression  in  the  lower  border  of  the  jaw 
near  the  symphysis;  the  tendon  is  held  to  the  hyoid  bone  by  an 
aponeurotic  loop  and  pierces  the  stylohyoid ;  action,  raises  the 
tongue  and  hyoid  bone ;  nerve,  mylohyoid  branch  of  the  inferior 
dental  and  facial. 

Stylohyoid  (m.  stylohyoideus) . — Origin,  from  outer  sur- 
face of  styloid  process;  insertion,  into  the  body  of  the  hyoid 
bone;  action,  retracts  and  elevates  the  hyoid  bone;  nerve,  facial: 
near  its  insertion  it  is  perforated  by  the  tendon  of  the  digastric. 

Mylohyoid  (m.  mylohyoideus)  .—Origin,  from  the  mylo- 
hyoid ridge  of  the  inferior  maxilla  from  last  molar  to  sym- 
physis; insertion,  into  a  fibrous  raphe  in  the  median  line, 
extending  from  the  hjroid  bone  to  the  chin  and  into  the  body 
of  the  hyoid  bone ;  action,  draws  forward  and  elevates  the  hyoid. 
bone  and  forms  part  of  the  floor  of  the  mouth ;  nerve,  mylohyoid 
branch  of  the  inferior  dental. 

Geniohyoid  (ra.  genioliyoideus). — Origin,  from  inferior 
genial  tubercle  of  the  internal  surface  of  the  symphysis  of  the 
jaw;  insertion,  into  the  front  of  the  body  of  the  hyoid  bone; 
action,  same  as  the  mylohyoid;  nerve],  hypoglossal. 


THE    MUSCULAR    SYSTEM.  I35 

MUSCLES    OF    THE    TONGUE. 

GtENIOHYOglossus  (111.  genioglossus) . — Origin,  from  supe- 
rior genial  tubercle  of  the  internal  surface  of  the  symphysis  of 
the  jaw:  insertion,  by  fanlike  expansion  into  the  whole  length 
of  the  inferior  surface  of  the  tongue,  the  side  of  the  pharynx, 
and  the  body  of  the  hyoid  bone;  action,  retracts  and  protrudes 
the  tongue;  nerve,  the  hypoglossal. 

Hyoglossus  (111.  hyoglossus). — Origin,  body  and  greater 
corrni  of  the  hyoid  bone;  insertion,  between  the  lingualis  and 
styloglossus  into  the  side  of  the  tongue;  action,  renders  the 
tongue  convex  from  side  to  side;  nerve,  hypoglossal. 

Styloglossus  (m.  styloglossus). — Origin,  from  stylomax- 
illary  ligament  and  styloid  process  of  tbe  temporal ;  m<  lertion, 
into  the  side  of-  the  tongue,  blending  with  the  hyogii  sSus  and 
lingualis;  action,  retracts  and  elevates  the  tongue;  nerve,  hypo- 
glossal. 

Lixgualis. — Consists  of  four  portions:  superior  lingualis 
(in.  longitudinal  is  superior),  very  superficial  from  base  to  apex, 
just  beneath  the  mucosa  of  the  dorsum;  inferior  lingualis  (m. 
iuiiijitudinalis  inferior),  two  muscle-bands  from  base  to  apex 
on  inferior  surface;  transversa  ''n'gualis  (m.  transversus  lin- 
gua), and  the  vertical  lingualis  („  .  verticeuis  Imgum),  as  indi- 
cated by  their  names,  send  transverse  fibers  between  the  superior 
and  inferior  muscles,  the  latter  sending  muscle-fibers  from  dor- 
sum to  mucosa  and  interlacing  with  the  other  muscles.  Action, 
renders  the  tongue  convex  from  before  backward';  nerve,  the 
chorda  tympani. 

Palatoglossus   (Constrictor  [sthmi  Faucium). 
Vide  Palatal  Region. 

PHARYNGEAL    AND    PALATAL    REGION. 

I  !ons  1  htctor  Superior  (m.  constrictor  pharyngis  superior). 
— Origin,  from  margin  of  internal  pterygoid  plate  and  its 
hamulai  process;  from  pterygomaxillary  ligament,  part  of  the 
alveolar  process  of  the  lower  jaw  and  side  of  the  tongue,  tendon 
of  the  tensor  palati,  and  part  of  the  palate  bone;  insertion,  into 
the  median  raphe  and  the  pharyngeal  spine  of  the  basilar  process 
of  the  occipital  hone;  action,  constricts  the  pharynx;  nerves, 
pharyngeal  plexus  and  glossopharyngeal. 

Constrictor  Medius  (m.  constrictor  pharyngis  medius). 
Origin,  from  the  stylohyoid  ligament,  greater  and  Lesser  cor- 
ona of  the  hyoid  hone;  insertion,  into  the  median  fibrous  raphe, 


136  HUMAN    ANATOMY. 

blending  with  its  fellow  of  opposite  side;  action,  constricts  the 
pharynx;  nerves,  pharyngeal  plexus  and  glossopharyngeal. 

Constrictor  Inferior  (m..  constrictor  pharyngis  inferior). 
— Origin^,  from  the  sides  of  the  thyroid  and  cricoid  cartilages; 
insertion,  into  the  fibrous  raphe  of  the  pharynx;  action,  con- 
tracts the  pharyngeal  canal;  nerves,  external  laryngeal,  glosso- 
pharyngeal plexus. 

Stylopharyngbus  (m.  stylopharyngeus) . — Origin,  from 
base  of  the  styloid  process;  insertion,  into  the  constrictor  mus- 
cles, palatopharyngeus,  and  posterior  border  of  the  thyroid 
cartilage ;  nerves,  pharyngeal  plexus  and  glossopharyngeal. 

Levator  Palati  (m.  levator  veli  palatini). — Origin,  carti- 
laginous portion  of  Eustachian  tube  and  apex  of  the  petrous 
portion  of  the  temporal  bone;  insertion,  into  the  back  part  of 
the  soft  palate,  blending  with  its  fellow  of  the  opposite  side; 
action,  elevates  the  soft  palate ;  nerve,  descending  palatine  from 
Meckel's  ganglion,  from  the  facial. 

Tensor  Palati,  or  Circumflexus  (m.  tensor  veli  pala- 
tini).— Origin,  from  spine  of  the  sphenoid,  vaginal  portion  of 
temporal  bone,  cartilage  of  Eustachian  tube,  and  scaphoid  fossa 
at  base  of  internal  pterygoid  plate;  insertion,  into  the  palate 
bone  and  the  soft  palate;  action,  renders  tense  the  palate;  nerve, 
a  branch  from  the  otic  ganglion. 

Azygos  Uvulae  (m.  uvulce). — Origin,  from  aponeurosis  of 
soft  palate  and  posterior  nasal  spine;  insertion,  into  the  uvula; 
action,  raises  the  palate;  nerves,  descending  palatine  branches 
and  Meckel's  ganglion,  from  the  facial. 

Palatoglossus  (m.  glossopalatinus) — Constrictor  Isth- 
mi  Faucium). — Origin,  from  soft  palate  on  either  side  of 
the  uvula;  insertion,  into  the  dorsum  and  side  of  the  tongue, 
blending  with  the  fibers  of  the  styloglossus — this  muscle  forms 
the  anterior  pillar  of  the  fauces;  action,  constricts  the  fauces; 
nerves,  palatine  branches  of  Meckel's  ganglion. 

Palatopharyngeus  (m.  pliaryngopalatinus). — Origin,  by 
two  portions,  from  soft  palate;  insertion,  into  posterior  border 
of  thyroid  cartilage  and  pharynx;  this  muscle  forms  the  pos- 
terior pillar  of  the  fauces;  action,  closes  the  posterior  nares; 
nerves,  palatine  branches  from  Meckel's  ganglion. 

VERTEBRAL    REGION. 

Pectus  Capitis  Anticus  Major. — Origin,  by  four  ten- 
dons from  transverse  processes  of  the  third,  fourth,  fifth  and 
sixth  cervical  vertebrae;  insertion,  basilar  process  of  occipital 


THE    MUSCULAK    SYSTEM.  137 

bone;  action,  flexes  the  head;  nerves,  suboccipital  and  deep 
internal  branches  of  cervical  plexus. 

Rectus  Capitis  Anticus  Minoe. — Origin,  from  root  of 
transverse  process  and  anterior  part  of  the  lateral  mass  of  the 
atlas;  insertion,  basilar  process  of  occipital,  behind  the  former; 
action,  flexes  the  head;  nerves,  suboccipital  and  deep  branches 
of  the  cervical  plexus. 

Rectus  Lateralis. — Origin,  superior  surface  of  the  trans- 
verse process  of  the  atlas;  insertion,  inferior  surface  of  the  jugu- 
lar process  of  the  occipital;  action,  draws  the  head  laterally; 
nerves,  suboccipital  and  deep  internal  branches  of  the  cervical 
plexus. 

Longus  Colli. — Origin,  from  three  portions,  superior  ob- 
lique portion  from  anterior  tubercles  of  the  transverse  processes 
of  the  third,  fourth  and  fifth  cervical ;  insertion,  tubercle  on 
the  anterior  arch  of  atlas ;  inferior  oblique  portion,  origin,  from 
anterior  surface  of  the  bodies  of  the  first  two  or  three  dorsal 
vertebras;  insertion],  anterior  tubercles  of  the  transverse  proc- 
-  -  of  the  fifth  and  sixth  cervical;  vertical  portion,  origin, 
from  the  anterior  surface  of  the  bodies  of  the  lower  three 
cervical  and  upper  three  dorsal  bodies  of  the  second,  third  and 
fourth  cervical  vertebras;  action,  rotates  and  flexes  the  cervical 
portion  of  the  vertebrae;  nerves,  anterior  branches  of  the  lower 
cervical  nerve. 

Scalenus  Anticus  (m.  scalenus  anterior). — Origin,  from 
the  tubercle  of  the  first  rib;  insertion,  into  the  anterior  tuber- 
cles of  the  transverse  processes  of  the  third,  fourth,  fifth  and 
sixth  cervical  vertebrae;  action,  flexes  and  rotates  the  vertebral 
column;  nerves,  anterior  branches  of  the  lower  cervical  nerve. 

Scalenus  Medius. — Origin,  upper  surface  of  the  first  rib, 
behind  the  groove  for  the  subclavian  artery;  insertion^  into  the 
transverse  processes  of  the  lower  six  cervical  vertebrae;  action, 
rotates  ami  flexes  the  vertebral  column;  nerves,  the  anterior 
branches  of  the  lower  cervical  nerve:  the  posterior  thoracic, 
long  thoracic  nerve,  or  external  respiratory  nerve  of  Bell,  has 
itfl  origin  in  the  substance  of  this  muscle,  by  union  of  two  roots 
from  fifth  and  sixth  cervical  nerves. 

x  LLENU8  Posticus  (m.  scalenus  posterior) . — Origin,  from 
the  outer  Burface  of  the  second  rib,  behind  the  serratus  magnus; 
insertion,  into  the  posterior  tubercles  of  the  transverse  processes 

of  the  lower  two  or  three  cervical  vertebrae;  ad  inn.  Ilexes  and 
rotates  the  -pine;  nerves,  anterior  branches  of  the  lower  cervical 
nerves. 


138  HUMAN    ANATOMY. 

Of  these  muscles  the  scalenus  medius  is  the  longest  and 
largest,  and  the  scalenus  posticus  the  smallest. 

Muscles  of  the  Larynx  and  Epiglottis  (vide  Larynx). 

Muscles   of  the  Trunk. 

muscles   of   the   back. 

First  Layer. 

Trapezius. — Origin,  from  inner  third  of  superior  curved 
line  of  the  occipital  bone,  the  ligamentum  nucha?,  the  spinous 
processes  of  the  seventh  cervical,  and  all  the  dorsal  vertebrae; 
insertion,  into  the  outer  third  of  the  posterior  border  of  the 
clavicle,  the  inner  margin  of  the  acromion  process,  and  the 
crest  of  the  spine  of  the  scapula ;  action,  with  head  fixed  elevates 
point  of  shoulder,  with  shoulders  fixed  together  draws  head 
backward,  or  singly  draws  head  to  corresponding  side;  adducts, 
rotates  inward  and  depresses  humerus;  nerves,  cervical  plexus 
and  spinal  accessory. 

Ligamentum  Nuchze. — Origin,  from  external  occipital 
protuberance;  insertion,  spinous  processes  of  the  cervical  verte- 
brae, from  the  second  to  the  seventh.  This  ligament  is  rudi- 
mental  in  man,  and  in  the  lower  animals  sustains  the  head. 

Latissimus  Dorsi. — Origin,  by  an  aponeurosis  from  the 
spinous  processes  of  the  six  lower  dorsal,  the  lumbar  and  sacral 
vertebrae,  the  supraspinous  ligament,  the  crest  of  the  ilium,  and 
the  three  or  four  lower  ribs;  insertion,  into  the  inner  lip  of  the 
bicipital  groove  of  the  humerus,  in  front  of  the  teres  major,  and 
a  little  above  the  pectoralis  major;  the  tendon  of  this  muscle 
twists  completely  on  itself,  so  that  the  superior  fibers  become 
the  inferior ;  action,  draws  the  arm  backward  and  downward,  or, 
fixing  the  arm,  raises  the  lower  ribs  and  draws  the  trunk  for- 
ward; nerve,  subscapular. 

Second  Layer. 

Levator  Anguli  Scapulae  (m.  levator  scapulce). — Origin, 
from  three  to  five  tendons  from  the  posterior  tubercles  of  the 
transverse  processes  of  the  three  or  five  upper  cervical  vertebrae ; 
insertion,  into  posterior  border  of  the  scapula,  at  the  root  of  the 
spine;  action,  elevates  the  angle  of  the  scapula;  nerve,  anterior 
division  of  the  third  and!  fourth  cervical  nerves. 

Ehomboideus  Minor. — Origin,  from  spinous  processes  of 
seventh  cervical  and  first  dorsal  vertebrae  and  the  ligamentum 
nuchas;  insertion,  into  root  of  the  spine  of  the  scapula;  action, 


THE    MUSCULAE    SYSTEM. 


139 


draws  the  inferior  angle  upward  and  backward;  nerves,  branches 
from  the  fifth  cervical  nerve. 

Rhomboidbus  Major. — Origin,  from  supraspinous  liga- 
ment and  spinous  processes  of  four  or  five  upper  dorsal  verte- 
brae;  insert wn.  by   a  tendinous  arch   attached   above  near  the 


Fig.  67. 

Muscle3  of  the  back:  1,  trapezius;  2,  4,  latissimus  dorsi;  10.  leva- 
tor anguli  scapulae;  11,  rhomboioVus  minor;  12.  rhomboideus  major; 
13,  14,  splenius  capitis  et  colli;  15,  vertebral  aponeurosis;  1G,  serratus 
posticus  inferior. 

-pine  and  below  to  the  inferior  angle  of  the  scapula:  action, 
draw-  the  inb-rior  angle  upward  and  backward;  nerves^  branches 
i.f  the  fifth  cervical. 

Third  Layer. 

Serrati  -  Postk  i  a  Supebiob  (//'.  serratus  posterior  supe- 
rior).    Orujiii.  from  spinous  processes  of  the  two  or  three  upper 


140  HUMAN   ANATOMY. 

dorsal  and  last  cervical  vertebras,  and  from  the  ligamentum 
nuchas;  insertion,  into  upper  borders  of  the  second  to  the  fifth 
ribs  inclusive;  action,  assists  in  respiration;  nerves,  external 
branches  of'  the  posterior  division  of  the  cervical. 

Serratus  Posticus  Inferior  (m.  serratus  posterior  infe- 
rior) .—Origin,  from  spinous  processes  and  interspinous  liga- 
ments of  two  or  three  upper  lumbar  and  two  lower  dorsal 
vertebrae;  insertion,  into  lower  borders  of  the  four  lower  ribs, 
external  to  their  angles;  action,  elevates  the  ribs;  assists  in 
respiration;  nerves,  external  branches  of  the  posterior  divisions 
of  the  lower  dorsal. 

Splenius. — Origin,  from  spinous  processes  of  last  cervical 
and  six  upper  dorsal  vertebra?,  the  lower  half  of  the  ligamentum 
nuchas,  and  the  supraspinous  ligament ;  insertion,  by  two  heads — 
splenius  capitis  (m.  splenius  capitis)  into  the  occipital  bone, 
just  below  the  superior  curved  line  and  the  mastoid  process  of 
the  temporal  bone;  splenius  colli  (m.  splenius  cervicis)  into  pos- 
terior tubercles  of  the  transverse  processes  of  the  three  or  four 
upper  cervical  vertebras;  action,  separately,  rotates  the  head  and 
draws  it  to  the  other  side;  together,  draw  the  head  back- 
ward; nerves,  external  branches  of  the  posterior  divisions  of  the 
cervical. 

Fourth   Layer. 

Erector  Spin^e  (m.  sacrospinalis) . — Origin,  from  sacro- 
iliac, groove  and  from  a  broad  tendon  attached  internally  to  the 
spinous  processes  of  the  lumbar  and  two  or  three  lower  dorsal 
vertebrae  and  supraspinous  ligament;  externally,  the  crest  of  the 
ilium  and  the  posterior  part  of  the  sacrum;  insertion,  by  two 
parts — (1)  sacrolumbalis  or  iliocostalis  (m.  iliocostalis  lum- 
borum),  inserted  into  the  angles  of  the  six  or  seven  lower  ribs; 
this  muscle  has  two  accessory  portions  (a)  musculus  acces- 
sorius  ad  iliocostalem  (m.  iliocostalis  dorsi)  :  origin,  from 
angle  of  six  lower  ribs;  insertion,  angles  of  six  upper  ribs; 
(&)  cervicalis  ascendens:  origin,  angles  of  the  four  or  five 
upper  ribs ;  insertion,  into  the  posterior  tubercles  of  the  fourth 
to  the  sixth  cervical  vertebras,  inclusive;  (2)  longissimus  dorsi; 
insertion,  into  the  transverse  processes  of  all  the  dorsal  vertebras, 
and  from  the  seventh  to  the  eleventh  ribs,  inclusive,  between 
their  angles  and  tubercles;  action,  bends  the  trunk  backward 
and  erects  the  spine;  nerves,  external  branches  of  the  posterior 
divisions  of  the  lumbar  and  dorsal. 

TplAnsversalis  Colli,  or  cervicis  (m.  longissimus  cervi- 
cis).— Origin,  transverse  processes  of  six  upper  dorsal  vertebras; 


THE    MUT3CULAK    SYSTEM.  141 

insertion:,  into  the  posterior  tubercles  of  the  transverse  proc- 
esses of  the  second  to  the  sixth  cervical  vertebra?  inclusive; 
nerves,  external  branches  of  the  posterior  divisions  of  the 
cervical. 

Trachelomastoid  (m.  longissimus  capitis). — Origin,  from 
articular  processes  of  three  or  four  lower  cervical,  and  from  the 
transverse  processes  of  the  third  to  the  sixth  dorsal  vertebrae; 
insertion,  into  the  posterior  margin  of  the  mastoid  process,  below 
the  sternomastoid  and  the  splenitis;  action,  steadies  the  head; 
nerves,  external  branches  of  the  posterior  divisions  of  the 
cervical. 

Spinalis  Dorsi. — Origin,  spinous  processes  of  last  two 
dorsal  and  first  two  lumbar  vertebrae;  insertion;  into  spinous 
processes  of  the  dorsal  vertebrae,  blending  with  the  semispinalis 
dorsi;  action,  erects  the  spinal  column;  nerves,  external  branches 
of  the  posterior  divisions  of  the  cervical. 

Spinalis  Cervicis,  or  spinalis  colli  (to.  spinalis  cervicis). 
— Origin,  from  the  spinous  processes  of  the  fifth  to  the  seventh 
cervical  vertebrae ;  insertion,  into  the  spinous  process  of  the  axis ; 
action,  steadies  the  neck;  nerves,  same  as  above;  this  muscle  is 
absent  in  20  per  cent,  of  the  subjects. 

Com  plexus  or  Semispinalis  Capitis  (to.  semispinalis 
capitis). — Origin,  by  seven  tendons  from  transverse  processes 
of  the  upper  three  dorsal  and  seventh  cervical  and  articular 
processes  of  the  fourth,  fifth  and  sixth  cervical;  insertion,  into 
the  occipital  bone,  between  the  curved  lines;  action,  separately, 
rotates  and  draws  the  head  to  one  side;  together,  draw  the  head 
directly  backward;  nerves,  suboccipital,  great  occipital,  and  in- 
ternal branches  of  the  posterior  divisions  of  the  cervical. 

Fifth  Layer. 

Semisi'Inales  Dorsi. — Origin,  from  transverse  processes 
from  the  fifth  to  eleventh  dorsal  vertebra1;  insertion,  into  the 
spinous  processes  of  the  lower  two  cervical  and  upper  four  dor- 
saJ  vertebrae;  action,  erects  the  spinal  column;  nerves,  internal 
branches  of  the  posterior  divisions  of  the  cervical. 

Semispinalis  Ceevicts,  oe  Colli  (to.  semispinalis  cervir 
ris). — Origin,  from  transverse  processes  of  lower  four  cervical 
and  upper  four  dorsal  vertebrae;  insertion,  into  spinous  proc- 
esses of  the  -••■oiid  to  the  fifth  cervical  vertebra?;  action,  erects 
the  spinal  column;  nerves,  same  as  above. 

.Mi  I/mini  s  Si-in.k  (m.  mvltifidus) . — Origin,  from  the 
transverse  processes  in  the  dorsal  region,  the  articular. processes 


142  HUMAN    ANATOMY. 

ill  the  cervical  and  lumbar  region,  the  posterior  superior  spine  of 
the  ilium,  posterior  sacroiliac  ligaments,  and  from  the  aponeu- 
rotic arch  of  the  erector  spinas;  insertion,  each  fasciculus  is 
attached  to  the  laminae  and  spinous  process  of  the  vertebras  above ; 
action,  preserves  the  erect  condition  of  the  spine ;  nerves,  internal 
branches  of  the  posterior  divisions  of  the  cervical,  dorsal,  lum- 
bar and  sacral  nerves, 

Botatores  Spiislze  (mm.  rotatores). — Eleven  on  either  side. 
Origin,  from  upper  part  of  transverse  process;  insertion,  into 
outer  surface  and  lower  border  of  the  laminae  of  the  vertebrae 
above,  from,  the  first  and  second  dorsal  to  the  eleventh  and 
twelfth;  action,  rotates  the  spinal  column;  nerves,  anterior 
branches  of  the  posterior  divisions  of  the  dorsal. 

Supraspinales. — Origin  and  insertion,  the  spinous  proc- 
esses in  the  cervical  region  of  the  vertebrae;  action,  extends 
cervical  spine;  nerves,  internal  branches  of  the  posterior  divi- 
sions of  the  cervical. 

Interspinales. — Consist  of  muscular  bands  in  pairs  be- 
tween the  spinous  processes  of  the  adjoining  vertebrae :  six  pairs 
in  the  cervical  region,  three  pairs  in  the  dorsal,  four  or  five'  in 
the  lumbar;  action,  extend  the  spine;  nerves,  internal  branches 
of  the  posterior  divisions  of  the  cervical  dorsal  and  lumbar. 

Extensor  Coccygis. — Origin,  from  the  first  piece  of  the 
coccyx,  or  last  bone  of  the  sacrum;  insertion,  into  the  lower 
extremity  of  the  coccyx;  action,  rudimental  in  man. 

Intertransversales  (mm.  intertransversarii) . — Are  small, 
muscular  bands  between  the  transverse  processes :  in  the  cer- 
vical regiom  seven  pairs,  in  the  dorsal  twelve  pairs,  in  the  lum- 
bar region  four  pairs;  action,  flex  the  spine  laterally;  nerves, 
internal  branches  of  the  posterior  division  of  the  cervical,  dor- 
sal and  lumbar. 

Bectus  Capitis  Posticus  Major  (m.  rectus  capitis  pos- 
terior major). — Origin,  from  the  spinous  process  of  the  axis; 
insertion,  into  inferior  curved  line  of  the  occipital  bone;  action, 
rotates  the  atlas  and  the  cranium ;  nerve,  the  suboccipital. 

Bectus  Capitis  Posticus  Minor  (m.  rectus  capitis  pos- 
terior  minor). — Origin,  from  the  tubercle  of  the  posterior  arch 
of  the  atlas;  insertion,  below  the  inferior  curved  line  of  the 
occipital  bone;  action,  draws  the  head  backward;  nerve,  sub- 
occipital. 

Obliquus  Capitis  Inferior.- — Origin,  spinous  process  of 
the  axis;  insertion,  lower  back  portion  of  the  transverse  process 
of  the  atlas;  action,  rotates  the  atlas  and  the  cranium;  nerves, 
suboccipital  and  great  occipital. 


THE    MUSCULAR    SYSTEM.  143 

Obliquus  Capitis  Superior. — From  upper  surface  of  the 
transverse  process  of  the  atlas;  insert  ion,  between  the  curved 
lines  of  the  occipital  bone  to  the  outer  side  of  the  complex  us ; 
action,  rotates  the  atlas;  nerves,  suboccipital  and  great  occipital. 

MUSCLES    OF    THE    ABDOMINOTHORACIC    REGION. 

Obliquus  Externus  {m.  obliquus  externus  abdominis).' — 
Origin,  lower  borders  of  the  eight  lower  ribs;  insertion,  the 
lowermost  muscular  fibers,  into  the  anterior  half  of  the  iliac 
crest ;  the  other  muscular  fibers,  by  a  broad  aponeurosis,  which 
joins  the  anterior  half  of  the  aponeurosis  of  the  internal  oblique 
to  form  the  anterior  walls  of  the  sheath  of  the  rectus,  above 
into  the  ensiform  cartilage,  below  into  the  symphysis  pubis.  In 
the  median  line  it  blends  with  its  fellow  of  the  opposite  side  to 
form  the  linea  alba.  A  slit  in  its  lower  portion  above  the  pubic 
spine  is  called  the  external  abdominal  ring.  The  lower,  thick- 
ened portion  of  the  aponeurosis  stretching  between  the  anterior 
superior  iliac  spine  and  the  pubic  spine  is  called  Poupart's  liga- 
ment, or  the  ligament  of  Fallopius.  A  reflection  from  it  to  the 
iliopectineal  line  is  called  Gimbernat's  ligament;  action,  flexes 
the  pelvis  on  the  thorax,  or  vice  versa,  and  compresses  the 
viscera :  nerves,  lower  intercostal,  iliohypogastric  and  ilioin- 
guinal. 

Obliquus  Internus,  or  internal  or  ascending  oblique  (m. 
obliquus  internus  abdominis). — Origin,  from  the  outer  half  of 
Poupart's  ligament,  from  the  anterior  two-thirds  of  the  crest 
of  the  ilium,  and  the  posterior  lamellae  of  the  lumbar  fascia; 
insertion,  above  to  the  lower  four  costal  cartilages,  below,  con- 
jointly with  the  tendon  of  the  transversalis,  into  the  os  pubis 
ami  linea  il iopeei inea,  to  form  the  conjoined  tendon  |  the  outer 
portion  of  this  tendon  being  termed  the  ligament  of  Ilesselbach 
(ligamentum  interfoveolare;  the  inner  part,  the  ligament  of 
Benle],  and  into  the  median  line  (linea  alba)  by  an  aponeurosis 
e  tending  from  the  sternum  and  seventh  and  eighth  costal  carti- 
iu  the  pubis.  This  aponeurosis  at  its  lower  fourth  consists 
of  two  united  lamina'  passing  in  front  of  the  rectus  muscle,  but 
in  its  upper  three-fourths  M.  divides,  one  lamina  passing  in  front 
of  the  rectus  and  joining  the  aponeurosis  of  the  externa!  oblique, 
ther  passing  behind  and  joining  the  aponeurosis  of  the 
transversalis;  action,  same  as  the  externus;  nerves,  same  as 
externus. 

Transversalis  (m.  fransversus  abdominis) .  Origm,  from 
outer  third  of  Poupart's  hgamenl   and  anterior  three-fourths  of 


144 


HUMAN    ANATOMY. 


the  crest  of  the  ilium,  from  the  inner  surface  of  the  cartilages 
of  the  six  lower  ribs,  and  from  the  spinous  and  transverse  proc- 
esses of  the  lumbar  vertebras ;  insertion,  by  the  conjoined  tendon 
into  the  linea  iliopectinea  and  crest  of  the  os  pubis;  action  and 
nerves,  same  as  the  externus. 


Fig.  68. 

Muscles  of  abdomen:     12,   external  oblique;   16,   rectus  abdominis;   18, 
internal  oblique;   17,   pyramidalis;   19,   quadratus  lumborum. 


Rectus  Abdominis. — Origin,  by  two  tendons — the  outer 
from  the  crest  of  the  pubis,  the  inner  interlacing  with  its  fellow 
of  the  opposite  side;  insertion,  into  the  cartilages  of  the  fifth, 
sixth  and  seventh  ribs;  action,  depresses  the  thorax,  flexes  the 
vertebral  column,  and,  acting  from  above,  flexes  the  pelvis  upon 
the  vertebral  column. 

Pyramidalis. — Origin,  from  the  os  pubis  and  anterior 
pubic  ligament;  insertion,  into  the  linea  alba,  midway  between 
the  os  pubis  and  umbilicus. 


THE    MUSCULAR    SYSTEM. 


145 


Quadratus  Lumboeum. — Origin,  by  two  portions — pos- 
terior portion,  from  crest  of  the  ilium  and  iliolumbar  ligament  ; 
insertion,  into  lower  border  of  the  last  rib  and  transverse  proc- 
esses of  the  three  lower  lumbar  vertebrae;  origin,  anterior  por- 
tion, from  upper  border  of  the  transverse  processes  of  the 
lumbar  vertebra?,  from  the  third  to  the  fifth;  insertion,  into 
one-half  the  lower  margin  of  the  last  rib  and  apices  of  upper 
four  lumbar  vertebras;  action,  draws  down  and  fixes  the  last  rib 
and  assists  in  inspiration  and  expiration. 


Fig.  69. 

Diaphragm:  1,  2,  3,  central  eordiform  tendon;  4,  middle  leaflet; 
5,  ligamentum  arcuatum  externum;  6,  ligamentum  arcuatum  inter- 
num; 8,  right  crus;  10,  left  crus;  11,  aortic  opening;  12,  esophageal 
opening;  13,  opening  for  vena  cava;  14,  psoas  magnus;  15,  quadratus 
lumborum. 


MUSCLES    OF    THE    THORAX. 

[ntebcostales    Externi    (mm.    intercostales    externi). — 

Eleven  pair-  ou  either  side.     Origin,  from  the  outer  bonier  of 
roove  on  the  lower  border  of  each  rib,  from  the  cartilage 
to  the  tubercle;  insertion,  into  upper  border  of  the  rib  below; 
nit  ion,  rai-es  the  ribs;  nerve,  intercostal. 

[ntercostales  Ixtkum  (mm.  intercostales  interni). — 
Origin,  inner  lip  of  the  groove  on  the  lower  border  of  each  rib; 
insert  ion,   into  tbe   upper  border  of  the  rib   below;  action,   pulls 

the  ribs  upward;  nerve,  intercostal. 

10 


146  HUMAN    ANATOMY. 

Infracostales — Subcostales  (mm.  subcostales). — Origin, 
inner  surface  of  rib ;  insertion,  into  the  inner  surface,  from  the 
first  to  the  third  rib  below;  action,  inspiratory  muscles;  nerve, 
intercostal. 

Triangularis  Sterni  (m.  transversus  thoracis). — Origin, 
lower  part  of  the  back  of  the  sternum  and  back  of  ensiform 
cartilage  and  inner  surface  of  sternal  end  of  the  costal  cartilages 
of  the  three  or  four  lower  ribs;  insertion,  into  the  border  and 
inner  surfaces  of  the  costal  cartilages,  from  the  second  to  the 
sixth  rib  inclusive  (it  is  continuous  below  with  transversalis 
abdominis  muscle);  action,  draws  down  the  costal  cartilages; 
nerve,  intercostal. 

Levatores  Costarum. — Twelve  on  either  side.  Origin, 
from  transverse  processes  of  seventh  cervical  and  eleven  upper 
dorsal  vertebrae;  insertion,  into  upper  surface  of  the  rib  below, 
between  the  angle  and  tubercle;  action,  raises  the  ribs;  nerve, 
the  intercostal. 

diaphragmatic   region. 

Diaphragm  (diapkragma) . — Origin,  inner  surface  of  ensi- 
form cartilage,  cartilages  and  bony  portions  of  six  or  seven  lower 
ribs  in  front,  and  from  two  aponeurotic  arches,  the  ligamentum 
arcuatum  externum  (arcus  lumbocostalis  lateralis)  and  inter- 
num (arcus  lumbocostalis  medialis) ,  and  the  lumbar  vertebra? 
behind  (pars  lumbalis)  ;  insertion,  into  the  circumference  of 
the  central  or  cordiform  tendon  (centrum  tendineum)  ;  action, 
the  principal  muscle  of  inspiration  and  expulsion;  nerves,  the 
phrenic,  and  phrenic  plexus  of  the  sympathetic. 

the  openings  in   the  diaphragm. 

The  aortic  opening  is  placed  posteriorly  between  the  two 
crura,  in  front  of  the  spine.  It  transmits  the  aorta,  thoracic 
duct,  and  vena  azygos  major,  and  sometimes  the  left  sympa- 
thetic nerve. 

The  esopliageal  opening  is  in  front  of  the  decussation  of 
the  crura,  a  little  to  the  left  and  in  front  of  the  aortic  opening 
(hiatus  aorticus) .  It  transmits  the  esophagus  and  pneumogas- 
tric  nerves. 

The  foramen  quadratum,  or  opening  (foramen  vena  cava}) 
for  the  vena  cava.,  is  placed  at  the  highest  part  of  the  central 
tendon,  a  little  to  the  right.  It  transmits  the  vena  cava  and 
maintains  its  jpatencx.  The  cms  on  each  side  transmits  the 
sympathetic  and  greater  and  lesser  splanchnic  nerves,  and  in 
addition  the  left  transmits  the  vena  azygos  minor, 


THE    MUSCULAK    SYSTEM.  U* 

Muscles  of  the   Perineum  (vide   Perineum). 

Muscles  of  the  Upper  Extremity. 

muscles   of  the  shoulder. 

Pectoralis  Major. — Origin,  from  the  sternal  half  of  the 
clavicle  (clavicular  portion)  and  anterior  surface  of  the  sternum 
and  costal  cartilages  from  the  second  to  the  sixth  or  seventh 
rib  (sternocostal  portion)  ;  insertion,  into  the  anterior  bicipital 
ridge  of  the  humerus;  action,  draws  the  arm  across  the  chest; 
nerves,  external  and  internal  anterior  thoracic. 

Pectoralis  Minor. — Origin,  upper  and  outer  surface  of 
the  third  to  the  fifth  rib,  inclusive,  and  the  aponeurosis  of  the 
intercostal  muscles;  insertion,  into  anterior  border  of  the  cor- 
acoid  process  of  the  scapula;  action,  draws  the  scapula  inward 
and  downward;  nerve,  the  anterior  thoracic. 

Subclavius. — Origin,  from  cartilage  of  the  first  rib ;  inser- 
tion, under  surface  of  the  clavicle,  about  its  middle  third ; 
action,  depresses  the  shoulder,  and  draws  clavicle  forward  and 
downward;  nerve,  branch  from  the  union  of  the  fifth  and  sixth 
cervical. 

Serratus  Magnus  (to.  serratus  anterior). — Origin,  by 
nine  muscular  portions,  from  the  outer  surface  of  the  eight 
upper  ribs  (two  divisions  being  from  the  second  rib)  and  from 
the  upper  intercostal  aponeurosis;  insertion,  by  three  divisions — 
upper  portion  into  superior  angle  of  the  scapula,  middle  portion 
into  posterior  portion  of  the  scapula  between  the  inferior  and 
superior  angles,  lower  portion  into  the  inferior  angle  of  the 
scapula;  action,  raises  the  vertebral  bonier  and  carries  the 
scapula  forward;  nerve,  the  posterior  thoracic. 

Deltoid  (to.  deltoideus). — Origin,  from  the  outer  third  of 
the  clavicle  and  from  the  outer  part  of  the  acromion  process  and 
the  lower  border  of  the  scapular  spine;  insertion,  into  the  outer 
side  of  the  -luit't  of  the  humerus,  about  its  middle  into  the  del- 
toid tubercle;  action,  raise-  the  arm;  nerve,  the  circumflex. 

Si  BSCAJP1  LABIS. — Origin,  from  the  internal  two-thirds  of 
the  subscapular  fossa;  insertion,  into  the  lesser  tuberosity  of  the 
humerus;  at  lion,  rotates  the  bead  of  the  humerus  inward; 
nerves,  upper  and  lower  subscapular. 

Supraspinatus. — Origin,  from  inner  two-thirds  of  supra- 
spinous fossa;  insertion,  into  the  uppermost  facet  of  the  greal 
tuberosity  of  the  humerus;  action,  assists  in  raising  the  arm 
and  fixing  the  head  of  the  humerus;  nerve,  the  suprascapular. 


148  HUMAN    ANATOMY. 

Infraspinatus. — Origin,  from  the  inner  two-thirds  of  the 
infraspinous  fossa;  insertion,  into  the  middle  facet  of  the  great 
tuberosity;  action,  rotates  the  head  of  the  humerus  outward; 
nerve,  suprascapular. 

Teres  Minor. — Origin,  posterior  surface  of  the  upper  two- 
thirds  of  the  axillary  border  of  the  scapula ;  insertion,  into  the 
lowest  facet  of  the  great  tuberosity;  action,  rotates  the  head  of 
the  humerus  outward;  nerve,  the  circumflex. 

Teres  Major. — Origin,  posterior  surface  of  the  inferior 
angle  of  the  scapula ;  insertion,  into  the  posterior  bicipital  ridge 
of  the  humerus ;  action,  draws  the  humerus  backward  and  down- 
ward, assisting  the  latissimus  dorsi;  nerve,  the  lower  sub- 
scapular. 

HUMERAL    REGION 

CoRACOBRAcniALis. — Origin,  from  apex  of  the  coracoid 
process  of  the  scapula;  insertion,  into  the  inner  side  of  the 
middle  of  the  shaft  of  the  humerus,  between  the  origin  of  the 
brachialis  anticus  and  short  humeral  head  of  the  triceps ;  action, 
draws  the  humerus  inward  and  forward;  nerves,  the  musculo- 
cutaneous and  a  branch  of  the  musculospiral. 

Biceps — Flexor  Cubiti  (to.  biceps  bracliii). — Origin,  by 
two  heads;  short  head  from  the  apex  of  the  coracoid  process, 
along  with  the  coracobrachialis ;  the  long  (glenoid)  head  {caput 
longum)  from  the  upper  margin  of  the  glenoid  cavity  of  the 
scapula;  insertion,  into  the  posterior  part  of  the  tuberosity  of 
the  radius;  action,  flexes  the  forearm;  nerve,  the  musculocu- 
>  ianeous. 

Brachialis  Anticus   (to.  brachialis) . — Origin,  inner  and 
outer  surfaces  of  the  shaft  of  the  humerus,  embracing  the  inser- 
tion of  the  deltoid;  insertion,  into  the  anterior  surface  of  the 
coronoid  process  of  the  ulna;  action,  flexes  the  forearm;  nerve, 
\     the  musculocutaneous. 

Triceps — Extensor  Cubiti  (to.  triceps  bracliii). — Origin, 
r  by  three  heads — middle,  or  scapular  head  (caput  longum),  below 
the  glenoid  cavity  of  the  scapula;  external  head  (caput  laterale), 
from  the  posterior  aspect  of  the  shaft  of  the  humerus,  between 
the  upper  part  of  the  musculospiral  groove  and  the  insertion  of 
the  teres  minor,  and  from  the  external  intermuscular  septum ; 
the  internal  head  (caput,  mediale),  from  the  posterior  aspect  of 
the  shaft  of  the  humerus,  below  the  insertion  of  the  teres  major, 
and  below  the  groove  for  the  musculospiral  nerve;  insertion,  by 
a  common  head,  into  the  posterior  part  of  the  under  surface  of 


THE    MUSCULAR    SYSTEM. 


14D 


the  olecranon  process  of  the  ulna;  action,  extends  the  forearm; 
nerve,  the  musculospiral. 

Subanconeus  (m.  anconceus) . — Origin,  from  the  posterior 
surface  of  the  humerus,  above  the  olecranon  fossa;  insertion, 
into  the  posterior  ligament  of  the  elbow-joint;  action,  draws  up 
the  posterior  ligament  of  the  elbow-joint  during  extension  of 
the  forearm;  nerve,  the  muscnlospiral. 


Fig.  70. 

Muscles  of  shoulder  and  arm;  4, 
subscapulars;  5,  teres  major;  G, 
coracobrachial  is;    7,    biceps. 


Fig.  71. 

Triceps  muscle:  1,  external  head; 
2,  scapular  head;  3,  internal  head; 
4,    insertion. 


MUSCLES    OF    THE    FOREARM. 

Anterior   Superficial  Layer. 

Phonatob  Radii  Teres  (w.  /initiator  tens). — Origin,  by 
two  heads — the  smaller  from  the  coronoid  process  of  the  ulna, 
the  ulnar  head  {caput  ulnare),  the  larger  from  the  humerus, 
the  internal  condyle,  the  humeral  head  (caput  numerate), 
and  from  the  common  tendon  of  this  group  of  muscles,  and 
intermuscular  Beptum;  insertion,  into  the  outer  aspeel  of  the 


150 


HUMAN    ANATOMY. 


shaft   of   the   radius;    action,   pronates   the    hand;    nerve,    the 
median. 

"Flexor  Carpi  Radialis. — Origin,  by  the  common  tendon 
from  the  inner  condyle,  and  from  the  intermuscular  septum 
between  it  and  the  pronator  teres;  insertion,  into  the  base  of 
the  metacarpal  bone  of  the  index  finger ;  action,  flexes  the  wrist ; 
nerve,  the  median. 


Fig.  72. 

Muscles  of  forearm:  1,  biceps;  2,  brachialis  anticus; 
supinator  longus;  5,  extensor  carpi  radialis  longior;  6, 
radialis  brevior;  8,  extensor  communis  digitorum;  12, 
ulnaris;    13,    14,    extensors   of   thumb. 


3,  triceps ;  4, 
extensor  carpi 
extensor     carpi 


Palmaris  Longus. — Origin,  from  the  inner  condyle  of  the 
humerus  by  the  common  tendon  and  the  intermuscular  septum 
and  the  deep  fascia;  insertion,  into  the  annular  ligament, 
spreading  out  in  the  palmar  fascia;  action,  renders  tense  the 
palmar  fascia;  nerve,  the  median. 


Till:    MUSCULAR    SYSTEM.  i;,l 

Fuexob  Caepi  Ulnabis. — Origin,  by  two  heads — one  by 
the  common  tendon  from  the  inner  condyle  of  the  humerus,  the 
other  from  the  inner  margin  of  the  olecranon,  the  intermuscular 
septum,  between  the  ulna  and  the  flexor  suhlimis  digitorum,  and 
from  the  upper  two-thirds  of  the  posterior  aspect  of  the  ulna; 
insertion^,  pisiform  hone;  action,  flexes  the  wrist;  nerve,  the 
ulnar. 

Flexor  Sublimis  Digitorum — Perforates  (m.  flexor 
digitorum  sublimis). — Origin,  by  three  heads — one  from  the 
coronoid  process  of  the  ulna,  the  ulnar  head  (caput  vlnare), 
above  the  pronator  radii  teres,  another  from  the  common  tendon 
from  the  internal  condyle  of  the  humerus,  the  humeral  head 
(caput  humerale),  and  the  third,  the  radial  head  (caput  radiale) 
from  the  oblique  line  of  the  radius,  from  the  insertion  of  the 
pronator  radii  teres,  to  the  tubercle;  each  tendon  divides  at  the 
base  of  the  first  phalanges  (chiasma  tendinum)  to  allow  the 
passage  of  the  tendon  of  the  flexor  profundus  digitorum;  inser- 
tion, into  the  lateral  margins  of  the  second  phalanges  by  four 
tendons;  action,  flexes  the  second  phalanges;  nerve,  median. 

Anterior  Veep  Layer. 

Flexor  Profundus  Digitorum — Perforaxs  (m.  flexor 
digitorum  profundus). — Origin,  from  the  inner  side  of  the 
coronoid  process,  and  from  the  upper  two-thirds  of  the  front 
ami  inner  aspect  of  the  shaft  of  the  ulna,  between  the  brachialis 
anticus  above  and  the  pronator  quadratus  below;  insertion,  by 
four  tendons  into  the  bases  of  the  last  phalanges,  perforating 
the  tendons  of  the  flexor  sublimis;  action.  Hexes  the  phalanges; 
nerves,  the  anterior  interosseous  and  the  ulnar. 

Plexob  Longus  Pollicis  (»'.  flexor  pollicis  longus). — 
Origin,  from  the  upper  two-thirds  of  the  shaft  of  the  radius  and 
from  tin'  interosseous  membrane;  insertion,  into  the  base  of  the 
last  phalanx  of  the  thumb;  action,  ilexes  the  phalanges;  nerve, 
the  anterior  interosseous. 

Pronator  Quadbatus. — Origin,  anterior  border  of  the 
ulna  and  from  the  oblique  line  of  the  lower  fourth  of  the 
anterior  aspeci  of  the  ulna;  insert  inn ,  into  the  lower  fourth  of 
the  front  and  outer  border  of  the  shaft  of  the  radius;  action, 
pronates  the  hand  ;  nerve,  anterior  interosseous. 

Radial  Region, 

-  pii  ltob  Lovers  (in.  Iivaeliinniiliiitis) .  Origin,  from 
the   upper   two-thirds   of  the  external   condyloid    ridge  of  the 


152  HUMAN   ANATOMY. 

humerus  and  the  external  intermuscular  septum;  insertion,  into 
the  base  of  the  styloid  process  of  the  radius;  action,  supinates 
the  hand ;  nerve,  musculospiral. 

Extensor  Carpi  Eadialis  Longior  (m.  extensor  carpi 
radialis  long  us). — Origin,  from  the  lower  third  of  the  external 
condyloid  ridge  of  the  humerus,  from  the  common  tendon  of 
the  extensor  muscles  of  the  forearm  from  the  external  condyle, 
and  the  intermuscular  septum;  insertion,  into  the  radial  side  of 
the  base  of  the  metacarpal  bone  of  the  index  finger;  action, 
extends  the  wrist;  nerve,  musculospiral. 

Extensor  Carpi  Eadialis  Brevior  (m.  extensor  carpi 
radialis  brevis). — Origin,  from  the  common  tendon  from  the 
external  condyle  of  the  humerus,  the  external  lateral  ligament, 
and  the  intermuscular  septum;  insertion,  into  the  base  of  the 
metacarpal  bone  of  the  middle  finger  on  its  radial  side;  action, 
extends  the  wrist;  nerve,  posterior  interosseous. 

Posterior    Superficial    Layer. 

Extensor  Communis  Digitorum  (m.  extensor  communis 
digitorum) . — Origin,  from  the  external  condyle  of  the  humerus, 
the  deep  fascia,  and  the  intermuscular  septa;  insertion,  by  four 
tendons  into  the  second  and  third  phalanges  of  all  the  fingers 
(at  the  first  phalanx  they  receive  the  insertion  of  the  lum- 
bricales  and  interossei)  ;  action,  extends  the  fingers;  nerve,  pos- 
terior interosseous. 

Extensor  Minimi  Digiti  (m.  extensor  digiti  quinti  pro- 
prius). — Origin,  from  the  common  tendon  from  the  external 
condyle  and  the  intermuscular  septum;  insertion,  into  the  sec- 
ond and  third  phalanges  of  the  little  finger ;  action,  extends  the 
little  finger;  nerve,  posterior  interosseous. 

Extensor  Carpi  Ulnaris. — Origin,  from  the  middle  third 
of  the  posterior  border  of  the  ulna,  from  the  common  tendon 
from  the  external  condyle  of  the  humerus,  and  from  the  fascia 
of  the  forearm;  insertion,  into  the  base  of  the  metacarpal  bone 
of  the  little  finger,  on  the  ulnar  side;  action,  extends  the  wrist; 
nerve,  posterior  interosseous. 

Anconeus  (m.  anconams). — Origin,  from  the  outer  con- 
dyle of  the  humerus;  insertion,  into  the  upper  fourth  of  the 
posterior  aspect  of  the  shaft  of  the  ulna  and  the  side  of  the 
olecranon;  action,  extends  the  forearm;  nerve,  musculospiral. 


THE    MUSCULAE    SYSTEM.  i;,;; 

Posterior  Deep    Layer. 

Supinator  Eadii  Brevis  (///.  supinator). — Origin,  from 
the  external  lateral  Ligament  of  the  elbow-joint,  from  the  exter- 
nal condyle  of  the  humerus,  from  the  ulna  below  the  lesser  sig- 
moid cavity,  and  from  the  orbicular  ligament  of  the  radius; 
insertion,  into  the  neck,  bicipital  tuberosity  and  oblique  line  of 
radius;  the  posterior  interosseous  nerve  pierces  this  muscle; 
n<  Hun,  supinates  the  hand;  nerve,  posterior  interosseous. 

Extensor  Ossis  Metacaepi  Pollicis  (m.  abductor  pollicis 
longus). — Origin,  middle  third  of  posterior  surface  of  radius, 
posterior  surface  of  lower  three-fourths  of  shaft  or  ulna,  ami 
interosseous  ligament;  insertion,  into  base  of  metacarpal  of 
thumb;  action,  extends  metacarpal  of  thumb;  nerve,  posterior 
interosseous. 

Extensor  Longus  Pollicis  (rn.  extensor  poll icis  longus). 
— Origin,  from  the  interosseous  membrane  and  from  the  pos- 
terior aspect  of  the  shaft  of  the  ulna  ;  insertion,  into  the  base  of 
the  last  or  terminal  phalanx  of  the  thumb;  action,  extends  the 
thumb;  nerve,  posterior  interosseous. 

Extensor  Brevis  Pollicis  (m.  extensor  pollicis  brevis).— 
Origin,  from  the  posterior  aspect  of  the  shaft  of  the  radius  and 
from  the  interosseous  membrane;  insertion,,  into  the  base  of  the 
first  phalanx  of  the  thumb  ;  action,  extends  the  thumb ;  nerve, 
posterior  interosseous. 

Extensor  Indicis  (m.  extensor  indicis  proprius). — Origin, 
from  the  posterior  aspect  of  the  ulna  and  from  the  interosseous 
membrane;  insertion,  into  the  second  and  third  phalanges  of 
the  index  linger,  along  with  the  tendon  of  the  extensor  com- 
munis: action,  extends  the  index  finger;  nerve,  posterior  inter- 
osseous. 

MUSCLES    OF    THE    HAND. 

These  are  divided  into  three  groups — the  radial  region,  the 
ulnar  region,  and  the  palmar  region. 

Radial    Region. 

Abductob  Pollicis  (/».  abductor  pollicis  brevis). — Origin. 
from  the  annular  ligamenl  and  ridge  of  the  trapezium;  inser- 
tion, into  base  of  the  first  phalanx  of  the  thumb  on  its  radial 
side;  action,  abducts  the  thumb  from  the  median  line;  nerve, 
median. 

0PPONEN8    I'oi.l.n  is.      Origin,    from   annular    ligament   and 

palmar  surf  ace  of  the  trapezium;  insertion,  into  metacarpal  bone 


154  HUMAN    ANATOMY. 

of  the  thumb  throughout  the  whole  length  of  its  radial  side; 
action,  flexes  the  first  metacarpal  bone ;  nerve,  median. 

Flexok  Brevis  Pollicis  (m.  flexor  pollicis brevis) . — This 
muscle  consists  of  two  portions.,  divided  by  tendon  of  flexor 
longus  pollicis;  origin,  superficial  portion  from  outer  two-thirds 
of  annular  ligament  and  trapezium,  deeper  portion  (by  some 
called  adductor  obliquus  pollicis)  from  sheath  of  flexor  carpi 
radialis,  the  trapezoid,  os  magnum,  and  base  of  first,  second, 
and  third  metacarpal  bones ;  insertion,  into  either  side  of  base 
of  first  phalanx  of  thumb,  the  inner  portion  joining  the  adduc- 
tor and  the  outer  portion  the  abductor;  each  tendon  has  a  sesa- 
moid bone  developed  in  it;  action,  adducts  thumb  toward  median 
line;  nerves,  ulnar  and  median. 

Adductor  Pollicis  (Adductor  Transversus  Pollicis). 
— Origin,  from  lower  two-thirds  palmar  surface  of  middle  meta- 
carpal bone;  insertion,  into  ulnar  side  of  base  of  first  thumb 
phalanx  and  internal  sesamoid  bone ;  action,  adducts  thumb ; 
nerve,  ulnar. 

Ulnar  Region. 

Palmaris  Brevis. — Origin,  from  palmar  fascia  and  annu- 
lar ligament;  insertion,  into  skin  of  palm  of  hand;  action, 
wrinkles  skin  of  hand;  nerve,  ulnar. 

Abductor  Minimi  Digiti  (m.  abductor  cligiti  quinti). — 
Origin,  from  pisiform  bone  and  from  tendon  of  flexor  carpi 
ulnaris;  insertion,  into  base  of  first  phalanx  of  little  finger  on 
its  ulnar  side;  action,  abducts  little  finger  from  median  line; 
nerve,  ulnar. 

Flexor  Brevis  Minimi  Digiti  (m.  flexor  digiti  quinti 
brevis). — Origin,  from  annular  ligament  and  tip  of  unciform 
process  of  unciform  bone;  insertion,  into  the  first  phalanx  of 
little  finger;  action,  flexes  little  finger;  nerve,  ulnar. 

Opponents  Minimi  Digiti  (m.  opponens  digiti  quinti). — 
Origin,  from  annular  ligament  and  from  unciform  process  of 
unciform  bone;  insertion,  into  ulnar  border  of  whole  length  of 
metacarpal  bone  of  little  finger;  action,  flexes  little  finger; 
nerve,  ulnar. 

Palmar  Region. 

Lumbricales. — Origin,  by  four  fleshy  tendons  from  the 
tendons  of  the  deep  flexors — the  first  and  second  from  the  pal- 
mar surface  and  radial  side  of  the  tendons  of  the  index  and 
middle  fingers,  the  third  from  the  adjoining  sides  of  the  ten- 
dons of-  the  middle  and  ring  fingers,  and  the  fourth  from  the 


THE    MUSCULAR    SYSTEM.  155 

adjoining  sides  of  the  tendons  of  the  ring  and  little  fingers ; 
insertion,  on  dorsal  aspect  of  each  finger  into  the  expansion  of 
the  extensor  communis  digitorum ;  action,  abduct  the  fingers  to 
either  side  of  the  median  line;  nerves,  ulnar  and  median. 

Ij&EROSSEI  -muscles  consist  of  two  groups,  the  dorsal  and 
palmar. 

Dorsal  Inteeossei  (mm.  interossei  dorsales). — Origin, 
from  two  heads  from  the  adjacent  sides  of  the  metacarpal  bones, 
four  in  number;  insertion,  the  first  into  the  radial  side  of  the 
base  of  the  first  phalanx  of  the  index  finger,  the  second  into  the 
radial  side  of  the  middle  finger,  the  third  into  the  ulnar  side 
of  the  middle  finger,  and  the  fourth  into  the  ulnar  side  of  the 
ring  finger,  the  middle  finger  having  two,  one  011  either  side; 
action,  abduct  the  fingers  from  the  median  line;  nerve,  ulnar. 

Palmar  Interossei  (mm.  interossei  volares). — Three  in 
number.  Origin,  the  first  from  the  entire  length  of  the  meta- 
carpal bone  of  the  index  finger  on  its  ulnar  side,  the  second  from 
the  ring  linger  on  its  radial  side,  and  the  third  from  the  little 
finger  on  its  radial  side;  insertion,  into  the  base  of  the  first 
phalanx  and  into  the  expansion  of  the  extensor  communis  ten- 
don of  the  same  finger  from  which  they  arise;  action,  adduct  the 
fingers  toward  the  median  line;  nerve,  ulnar. 

Muscles   of   the  Lower    Extremity, 
iliac   region. 

Psoas  Magnus  (m.  psoas  major). — Origin,  from  the  sides 
and  anterior  surfaces  of  the  transverse  processes  and  bodies  of 
the  last  dorsal  and  all  the  lumbar  vertebrae  and  the  interver- 
tebral substances  between  them;  insertion,  into  the  lesser  tro- 
chanter of  the  femur,  unting  with  the  tendon  of  the  iliacus; 
this  muscle  is  in  relation  behind  with  the  capsular  ligament  of 
the  nip,  being  separated  from  it  by  a  synovial  bursa;  act  inn. 
and  rotates  the  femur  inward,  and  also  flexes  the  trunk 
and  pelvis  on  the  thigh;  nerves,  anterior  branches  of  the  lum- 
bar nerves. 

Psoas  Pabvus  (m.  psoas  minor). — Origin,  from  the  lateral 
Burfacee  of  the  bodies  of  the  Las!  dorsal  and  first  Lumbar  vertebrae 
and  from  the  intervertebral  substances  between  them;  insertion. 
into  tin*  iliopectinea]  eminence,  joining  the  iliac  fascia;  action . 
assists  the  psoas  magnue  and  renders  tense  the  iliac  fascia; 
nerves,  anterior  branches  of  the  lumbar. 

[liacus.     Origin,  from  the  base  of  the  sacrum  and  the  ilio 
lumbar  Ligament  behind,  from,  the  iliac  fossa  and  inner  margin 


156  HUMAN    ANATOMY. 

of  the  crest  of  the  ilium  and  the  anterior  superior  and!  ante- 
rior inferior  spinous  processes  of  the  ilium;  insertion,  into  the 
oblique  or  intertrochanteric  line  of  the  femur  to  the  outer  side 
of  the  insertion  of  the  psoas;  action,  flexes  and  rotates  the 
femur  inward  and  flexes  the  trunk  and  pelvis  on  the  thigh; 
nerves,  anterior  crural  and  the  anterior  branches  of  the  lumbar. 

FEMORAL    AND    GLUTEAL    REGION. 

Tensor  Vaginae  FEmoris,  or  tensor  fasciae  femoris  (m. 
tensor  vagina?  femoris,  or  m.  tensor  fascia?  femoris) . — Origin, 
from  the  anterior  superior  spinous  process  between  the  sartorius 
and  the  gluteus  medius,  and  from  the  fore  part  of  the  outer  lip 
of  the  crest  of  the  ilium;  insertion,  into  the  fascia  lata,  about 
the  upper  fourth  of  the  outer  side  of  the  thigh ;  action,  renders 
tense  the  fascia  lata;  nerve,  superior  gluteal. 

Sartorius. — Origin,  from  the  anterior  superior  spinous 
process  of  the  ilium  and  the  upper  part  of  the  notch  below; 
insertion,  into  the  inner  and  upper  part  of  the  shaft  of  the 
tibia;  action,  flexes  the  leg  upon  the  thigh  and  the  thigh  upon 
the  pelvis;  nerve,  branches  of  the  anterior  crural. 

Quadriceps  Extensor  (to.  quadriceps  femoris). — This 
extensive  muscle  covers  the  front  and  sides  of  the  femur  and 
consists  of  four  portions — the  rectus  femoris,  the  vastus  exter- 
nus,  the  vastus  interims  and  the  crureus. 

Rectus  Femoris. — Origin,  by  two  heads — one,  the  long 
head,  from  the  groove  above  the  brim  of  the  acetabulum;  the 
other,  the  short  head,  from  the  anterior  inferior  spinous  process 
of  the  ilium ;  insertion,  by  the  common  tendon  into  the  patella ; 
action,  extends  the  leg  upon  the  thigh ;  nerves,  branches  of  the 
anterior  crural. 

Vastus  Externus  (m.  vastus  lateralis). — Forms  the 
greater  part  of  the  quadriceps  extensor.  Origin,  by  an  exten- 
sive aponeurosis  extending  from  the  tubercle  of  the  femur  along 
the  anterior  border  of  the  great  trochanter  and  the  whole  length 
of  the  outer  lip  of  the  linea  aspera;  insertion,  into  the  outer 
portion  of  the  patella,  joining  the  common  tendon;  action, 
extends  the  leg  on  the  thigh;  nerves,  branches  of  the  anterior 
crural. 

Vastus  Internus  and  Crureus  (m.  vastus  medialis  el  m. 
vastus  intermedins)  .■ — Origin,  by  a  tendinous  aponeurosis  ex- 
tending from  the  neck  of  the  femur  throughout  the  whole  length 
of  the  inner  lip  of  the  linea  aspera ;  insertion,  into  the  common 
tendon,  together  with  the  rectus  femoris  and  the  vastus  exter- 


THE    MUSCULAR    SYSTEM. 


157 


mis;  action,  extends  the  leg  on  the  thigh;  nerves,  branches  of 
the  anterior  crural. 

Subcrureus  (m.  articularis  genu). — Origin,  from  the  an- 
terior aspect  of  the  lower  part  of  the  shaft  of  the  femur ;  inser- 
tion, into  the  synovial  sac  behind  the  patella. 


Fig.  73. 

Anterior  femoral  re- 
gion ;  4,  tensor  vaginae 
femoris;  5,  sartorius;  6, 
rectus;  7,  vastus  exter- 
nus;  8,  vastus  internus; 
10,  iliacus;  11,  psoas;  12, 
pi  i  t  ineus;  13,  adductor 
longus;  14,  adductor  mag- 
nus;    16,    gracilis. 


Fig.  74. 

Posterior  femoral  re- 
gion; 1,  gluteus  medius; 
2,  gluteus  rnaximus;  3, 
vastus  externus;  4,  bi- 
ceps; 0,  semitendinosus; 
7,  semimembranosus;  s, 
gracilis. 


GRACILIS. — Origin ,  from  the  inner  margin  of  the  ramus  ->l 
the  ischium  and  the  pubes ;  insertion,  into  the  innei  asped  "I' 
the  -haft  <»f  the  tibia,  below  the  tuberosity;  action,  flexes  the 


158  HUMAN    ANATOMY. 

leg  and  draws  it  inward,  assisting  the  sartorius;  nerve,  the 
obturator. 

Pectineus. — Origin,  from  the  tendinous  prolongation  of 
Gimbernat's  ligament  and  the  linea  iliopectinea ;  insertion,  into 
the  rough  line  leading  to  the  linea  aspera  from  the  lesser  tro- 
chanter ;  action,  adducts  the  thigh ;  nerves,  obturator,  the  acces- 
sory obturator,  and  branches  of  the  anterior  crural. 

Adductor  Longus. — Origin,  from  the  front  of  the  os  pubis 
below  the  crest;  insertion,  into  the  middle  third  of  the  linea 
aspera,  between  the  adductor  magnus  and  the  vastus  internus ; 
action,  adducts  the  thigh;  nerve,  obturator. 

Adductor  Brevis. — Origin,  from  the  outer  aspect  of  the 
descending  ramus  of  the  pubes,  between  obturator  externus  and 
the  gracilis;  insertion,  into  the  upper  part  of  the  linea  aspera; 
action,  adducts  the  thigh;  nerves,  branches  of  the  obturator. 

Adductor  Magnus. — Origin,  from  the  tuberosity  of  the 
ischium,  the  ascending  ramus  of  the  ischium,  and  from  the 
descending  ramus  of  the  pubes;  insertion,  into  the  rough  line 
leading  to  the  linea  aspera  from  the  great  trochanter  to  the 
inner  side  of  the  gluteus  maximus  and  into  the  adductor  tuber- 
cle above  the  inner  condyle  of  the  femur  {vide  page  64)  ;  action, 
adducts  the  thigh;  nerves,  the  obturator  and  a  branch  from  the 
great  sciatic. 

Gluteus  Maximus  (m.  glutceus  maximus). — Origin,  from 
the  superior  curved  line  of  the  ilium,  the  posterior  aspect  of  the 
last  segment  of  the  sacrum,  the  border  of  the  coccyx,  and  the 
surface  of  the  great  sacrosciatic  and  posterior  sacroiliac  liga- 
ments ;  insertion,  into'  the  rough  line  leading  to  the  linea  aspera 
from  the  great  trochanter,  between  the  adductor  magnus  and 
the  vastus  externus,  and  into  the  fascia  lata;  action,  it  is  a  ten- 
sor of  the  fascia  lata,  and  .an  external  rotator  and  extensor  of 
the  thigh;  nerves,  the  inferior  gluteal  and  a  branch  from  the 
sacral  plexus. 

Gluteus  Medius  (m.  glutceus  medius). — Origin,  from  the 
outer  lip  of  the  crest  and  the  outer  aspect  of  the  ilium,  between 
the  middle  and  superior  curved  lines,  and  from  the  gluteal  apo- 
neurosis; insertion,  into  the  oblique  line  on  the  outer  surface  of 
the  great  trochanter;  action,  rotates  the  thigh  outward;  nerve, 
from  the  superior  gluteal. 

Gluteus  Minimus  (m.  glutceus  minimus). — Origin,  from 
the  border  of  the  great  sacrosciatic  notch  and  between  the  infe- 
rior and  middle  curved  lines  of  the  outer  aspect  of  the  ilium; 
insertion,  into  a  depression  on  the  front  border  of  the  great 


THE    MUSCULAR    SYSTEM.  i.v.i 

trochanter;  action,  rotates  the  thigh  inward;  nerve,  superior 
gluteal. 

PYEIFORMIS  (in.  piriformis). — Origin,  from  the  anterior 
surface  of  the  sacrum,  between  the  first  to  the  fourth  anterior 
sacral  foramen,  and  from  the  margin  of  the  great  sacrosciatic 
foramen,  and  from  the  anterior  aspect  of  the  great  sacrosciatic 
ligament;  insertion ,  into  the  upper  border  of  the  great  tro- 
chanter, with  the  tendon  of  the  obturator  interims;  action. 
rotates  femur  outward;  nerve,  obturator. 

Obturator  Intbenus. — Origin,  from  the  inner  side  of  the 
obturator  foramen  and  the  internal  surface  of  obturator  mem- 
brane and  the  anterior  and  external  wall  of  the  pelvis;  it  passes 
out  of  the  pelvis  through  the  lesser  sacrosciatic  notch  and 
receives  the  tendons  of  the  gemelli  muscles;  insertion,  into  the 
upper  border  of  the  great  trochanter  in  front  of  the  pyriformis; 
action,  rotates  the  thigh  outward;  nerves,  branches  from  the 
sacral  plexus. 

Gemelli  consist  of  two  muscles — gemellus  superior  and 
gemellus  inferior. 

G-emellus  Superior. — Origin,  from  the  outer  aspect  of 
the  spine  of  the  ischium;  insertion,  into  the  tendon  of  the 
obturator  interims. 

Gemellus  Inferior. — Origin,  from  the  outer  border  of 
tuberosity  of  the  ischium;  insertion,  into  the  lower  portion  of 
the  tendon  of  the  obturator  interims ;  action,  rotates  the  thigh 
outward;  nerves,  branches  of  the  sacral  plexus. 

Quadrattjs  Femoris. — Origin,  from  the  external  border  of 
the  tuberosity  of  the  ischium;  insertion,  into  the  upper  part  of 
the  linea  quadrati,  on  the  posterior  aspect  of  the  trochanter 
major;  action,  rotates  the  thigh  outward;  nerves,  branches  of 
the  sacral  plexus. 

Obturator  Exterxus. — Origin,  from  the  inner  two-thirds 
of  the  anterior  aspect  of  the  obturator  membrane  and  the  ten- 
dinons  arch  covering  the  canal  for  the  obturator  vessels  and 
nerves,  and  the  descending  ramus  of  the  pubis  and  the  ascend- 
ing ramus  of  the  ischium;  insertion,  into  the  digital  fossa  of  the 
femur;  action,  rotates  the  thigh  outward;  nerve,  the  obturator. 

Bn  EPS,  or  biceps  flexoT  cruris(wi.  l>i<<-jis  femoris). — Origin, 
arises  by  two  heads — the  long  head  [caput  longum),  from  the 
lower  and  inner  facet  of  the  tuberosity  of  the  ischium  by  a 
'•oiiiiiion  tendon  to  the  long  head  of  the  seinitendinostis ;  the 
short  bead  (caput  breve),  from  the  outer  lip  of  the  linea  aspera, 
tween  the  vastus  externue  ami  the  adductor  magnus;  insertion, 

outer  ?-id<j  of  head   of  fibula,  by  two  portions,  on  either  side  of 


160  HUMAN    ANATOMY. 

the  external  lateral  ligament  of  the  knee  joint,  sending  a  band 
forward  to  the  outer  tuberosity  of  the  tibia.  This  tendon  forms 
the  outer  hamstring;  action,  flexes  the  leg  upon  the  thigh ;  nerve, 
the  great  sciatic. 

Semitendinosus. — Origin,  from  a  common  tendon,  to- 
gether with  the  long  head  of  the  biceps,  from  the  tuberosity  of 
the  ischium;  insertion,  into  the  inner  and  upper  part  of  the 
shaft  of  the  tibia;  action,  rotates  the  leg  inward;  nerve,  the 
great  sciatic. 

Semimembranosus. — Origin,  from  the  outer  and  upper 
facet  of  the  tuberosity  of  the  ischium  to  the  outer  side  and  above 
the  origin  of  the  semimembranosus  and  the  biceps ;  insertion, 
into  the  posterior  inner  aspect  of  the  inner  tuberosity  of  the 
tibia,  under  the  internal  lateral  ligament  by  three  portions — the 
internal  portion  into  the  inner  side  of  the  internal  tuberosity, 
the  posterior  portion  into  the  posterior  part  of  the  outer  con- 
dyle of  the  femur,  forming  the  principal  part  of  the  posterior 
ligament  of  the  knee  joint,  and  middle  portion  into  the  poste- 
rior aspect  of  the  inner  tuberosity;  action,  flexes  the  leg  upon 
the  thigh;  nerve,  the  great  sciatic. 

These  two  tendons  (semimembranosus  and  semitendino- 
sus),  together  with  the  gracilis  and  sartorius,  form  the  inner 
hamstring. 

MUSCLES    OF    THE    LEG. 

Anterior  Set. 

Tibialis  Anticus  (m.  tibialis  anterior). — Origin,  from 
the  upper  and  outer  two-thirds  of  the  shaft  of  the  tibia,  the 
interosseous  membrane,  and  the  intermuscular  septum  between 
it  and  the  extensor  longus  digitorum;  insertion,  into  the  lower 
and  inner  aspect  of  the  internal  cuneiform  bone  and  base  of  the 
first  metatarsal  bone;  action,  flexes  the  foot;  nerve,  the  anterior 
tibial. 

Extensor  Proprius  Pollicis  (to.  extensor  liallucis  lon- 
gus).— Origin,  from  the  anterior  aspect  of  the  fibula  and  the 
interosseous  membrane  and  the  intermuscular  septum  between 
it  and  the  extensor  longus  digitorum;  insertion,  into  the  base 
of  the  last  phalanx  of  the  great  toe;  action,  extends  the  great 
toe;  nerve,  the  anterior  tibial. 

Extensor  Longus  Digitorum  (m.  extensor  digitorum.  lon- 
gus).— Origin,  from  the  upper  two-thirds  of  the  anterior  aspect 
of  the  shaft  of  the  fibula  and  the  outer  tuberosity  of  the  tibia, 
from  the  deep  fascia  of  the  interosseous  membrane  and  the 


THE    MUSCULAR    SYSTEM. 


161 


intermuscular  septum,  between  it  and  the  perinei  on  the  outer 
and  the  tibialis  anticus  on  the  inner  side;  insertion,  by  three 
tendons  into  the  bases  of  the  first  and  second  phalanges  of  the 
four  lesser  toes,  the  innermost  tendon  dividing  into  two;  each 
tendon   (except  the  fourth)    is  joined  opposite  the  metatarso- 


FiG.  75. 

Anterior  muscles  of  leg;  3,  tibialis 
anticus;  4,  extensor  longus  digi- 
torum;  5,  extensor  proprius  pollicis; 
6,  i"  roneus  tertius;  7,  peroneus  lon- 
gus;   8,    peroneus   brevis. 


Fig.  76. 

Posterior  muscles  of  leg;  4,  pop- 
liteus;  5,  gastrocnemius;  6,  tenda 
Achillis;  8,  tendons  of  peroneus  lon- 
gus and  brevis;  9,  tibialis  posticus 
and    flexors. 


phalangeal  joint  by  the  tendon  of  the  extensor  brevis  digitorum, 
and  receives  an  expansion  from  the  lumbricales  and  inteiossei; 
at  the  first  interphalangeal  articulation  the  tendons  divide  into 
three  slips — the  middle  one  for  insertion  into  the  second  pha- 
lanx, and    the  olhcr   two   uniting  to   be    inserted    into   the   base 


11 


162  HUMAN    ANATOMY. 

of  the  third;  action,  extends  the  phalanges  and,   continuing, 
flexes  the  foot  npon  the  leg;  nerve,  the  anterior  tibial. 

Peroneus  Tertius  (ra.  peronams  tertius). — Origin,  from 
the  lower  front  part  of  the  fibula  on  its  outer  side,  from  the 
interosseous  membrane,  and  the  intermuscular  septum  between 
it  and  the  peroneus  brevis;  insertion,  into  the  metatarsal  bone 
of  the  little  toe;  action,  flexes  the  tarsus  upon  the  leg;  nerve, 
the  anterior  tibial. 

Posterior  Superficial   Set. 

Gastrocnemius. — Origin,  from  the  upper  and  back  part 
of  the  external  and  internal  condyles  of  the  femur  on  either 
side,  above  the  origin  of  the  popliteus,  and  from  the  supracon- 
dyloid  ridges;  insertion,  by  joining  with  the  tendon  of  the  soleus 
to  form  the  tendo  Achillis ;  action,  extends  the  foot ;  nerve),  from 
the  internal  popliteal. 

Soleus. — Origin,  from  the  oblique  line  of  the  tibia,  from 
the  middle  third  of  the  internal  border,  and  from  the  posterior 
surface  of  the  head  of  the  fibula;  insertion,  by  joining  with  the 
tendon  of  the  gastrocnemius  to  form  the  tendo  Achillis ;  action, 
extends  the  foot;  nerve,  the  internal  popliteal. 

Tendo  Achillis  (tendo  calcaneus). — Origin,  from  the 
union  of  the  gastrocnemius  and  soleus;  is  the  largest  and  strong- 
est tendon  in  the  body;  it  is  inserted  into  the  inferior  surface 
of  the  posterior  tuberosity  of  the  os  calcis,  having  a  synovial 
bursa  (bursa  tendinis  calcanei  [Achillis])  between  it  and  the 
bone. 

Plantaris. — Origin,  from  the  posterior  ligament  of  the 
knee-joint  and  the  lower  portion  of  the  outer  division  of  the 
linea  aspera;  insertion,  into  the  posterior  part  of  the  os  calcis 
to  the  inner  side  of  the  tendo  Achillis;  action,  the  rudiment  of 
a  muscle  intended  to  render  tense  the  plantar  fascia ;  nerve,  the 
internal  popliteal. 

Posterior  Deep  Set. 

Popliteus. — Origin,  from  the  outer  side  of  the  external 
condyle,  from  the  posterior  ligament  of  the  knee-joint;  inser- 
tion, above  the  oblique  line  on  the  posterior  aspect  of  the  shaft 
of  the  tibia;  action,  assists  in  flexing  the  leg;  nerve,  the  internal 
popliteal. 

Flexor  Longus  Hallucis  (ra.  flexor  hallucis). — Origin, 
from  the  lower  two-thirds  of  the  internal  surface  of  the  fibula, 
from  the  lower  part  of  the  interosseous  membrane,  fascia  cov- 


THE    MUSCULAR    SYSTEM. 


163 


ering  tibialis  posticus,  and  from  the  intermuscular  septum;  n 
passes  behind  the  internal  malleolus;  insertion,  into  the  base  of 
the  last  phalanx  of  the  great  toe;  nerve,  posterior  tibial. 

Flexor  Long  us  Digitorum — Pereorans  (ra.  flexor  digi 
torn  in  longus) . — Origin,  from  the  posterior  aspect  of  the  tibia. 
below  the  oblique  line;  it  passes  behind  the  internal  malleolus- 
insertion,  into  the  bases  of  the  last  phalanges  of  the  four  lesser 
toes,  passing-  through  the  division  in  the  tendons  of  the  flexor 
brevis  digitorum;  action,  flexes  the  phalanges  and.  continuing, 
extends  the  foot  on  the  leg;  inrrr,  the  posterior  tibial. 

Tibialis  Posticus  (m.  tibialis  posterior) .—Origin  from 
the  posterior  aspect  of  the  shaft  of  the  tibia,  and  from  the  upper 
two-thirds  of  the  shaft  of  the  fibula,  and  from  the  whole  length 
of  the  interosseous  membrane  and  the  intermuscular  septa  on 
either  side  of  it;  it  passes  behind  the  inner  malleolus;  insertion, 
into  the  internal  cuneiform  bone  and  the  tuberosity  of  the  sca- 
phoid ;  it  contains  a  sesamoid  bone  in  its  tendon;  action,  extends 
the  tarsus  upon  the  leg;  nerve,  the  posterior  tibial. 

Fibular  Region. 

Peroneus  Longus  (m.  peronceus  longus). — Origin  from 
the  upper  two-thirds  of  the  shaft  of  the  fibula,  the  head  of  the 
fibula,  the  intermuscular  septa,  and  the  deep  fascia;  it  passes 
behind  the  outer  malleolus  along  with  the  peroneus  brevis- 
insertion,,  into  the  base  of  the  metatarsal  bone  of  the  great  toe; 
this  tendon  changes  its  course  twice,  first  at  the  external  mal- 
colu-,  second  at  the  cuboid  bone,  and  usually  has  a  sesamoid 
bone  developed  in  its  tendon;  action,  extends  and  everts  the  foot 
upon   the  leg;  nerve,  musculocutaneous  branch  of  the  external 

popliteal. 

Peroneus  Brevis  (m.  peronmis  brevis)  .—Origin,  from  the 
outer.  and  middle  third  of  the  m,„la  :lnd  the  intermuscular  septa 
on  either  sid,.;  insertion,  into  the  upper  surface  of  the  base  of 
the  metatarsal  bone  of  the  little  toe;  action,  extends  the  foot 
"1"")  the  leg;  nerve,  musculocutaneous  branch  of  the  external 
popliteal. 

MUSCLES    of    THE    FOOT. 

Dorsal  Region. 

Extbnsob  Brevis  Digitorum  (m.  extensor  digitorum 
brevw)  Origin,  from  the  external  calcaneoastragaloid  liga- 
ment,  Iron,   the   annular   ligament,  and    from   the  oilier  side' of 


164  HUMAN    ANATOMY. 

the  os  calcis;  insertion,  by  four  tendons — the  first  one  into  the 
first  phalanx  of  the  great  toe,  the  other  three  into  the  long 
extensor  tendons  of  the  second,  third,  and  fourth  toes  on  their 
outer  sides;  action,  extends  the  phalanges  of  the  four  inner  toes 
and  the  first  phalanx  of  the  great  toe ;  nerve,  the  anterior  tibial. 

Plantar  Region. 
The  muscles  of  this  region  are  divided  into  four  sets. 

First  Set. 

Abductor  Hallucis. — Origin,  from  the  internal  annular 
ligament,  from  the  inner  tubercle  of  the  os  calcis,  from  the 
intermuscular  septum  on  its  outer  side  and  plantar  fascia ;  inser- 
tion, into  the  base  of  the  first  phalanx  of  the  great  toe  on  its 
inner  side;  action,  abducts  the  great  toe;  nerve,  branch  of  the 
internal  plantar. 

Plexor  Brevis  Digitorum — Perforatum  (ra.  flexor  digi- 
torum brevis). — Origin,  from  the  inner  tubercle  of  the  os  calcis, 
from  the  plantar  fascia  and  the  intermuscular  septa  between  it 
and  the  muscles  on  either  side;  insertion,  into  the  second 
phalanges  by  a  process  on  either  side,  allowing  the  passage  of 
the  tendon  of  the  flexor  longus  digitorum;  action,  flexes  second 
phalanges  upon  first  and  continuing  may  flex  first  phalanges 
bringing  toes  together;  nerve,,  from  the  internal  plantar. 

Abductor  Minimi  Digiti  (m.  abductor  digiti  quinti). — 
Origin,  from  the  plantar  fascia,  from  the  os  calcis  in  front  of 
the  tubercle,  and  from  the  intermuscular  septum  on  its  inner 
side;  insertion,  into  the  first  phalanx  of  the  little  toe  on  its 
outer  side;  action,  abducts  little  toe;  nerve,  external  plantar. 

Second  Set. 

Flexor  Accessorius  (m.  quadratus  plantar). — Origin,  by 
two  heads,  one  from  the  os  calcis  in  front  of  the  outer  tubercle, 
the  other  from  the  inner  surface  of  the  os  calcis  and  the  cal- 
caneoscaphoid  ligament;  insertion,  by  a  common  tendon  into 
the  tendon  of  the  flexor  longus  digitorum;  action,  accessory  to 
the  long  flexor;  nerve,  external' plantar. 

Lumbricales. — Four  small  muscles.  Origin,  from  the  ten- 
dons of  the  flexor  longus  digitorum,  after  their  division,  each 
one  arising  from  two  tendons;  insertion,  into,  the  base  of  the 
first  phalanx  of  the  same  toe  and  the  tendinous  expansion  of 
the  extensor  longus  digitorum;  nerves,  the  external  plantar 
nerve  supplies  the  two  external,  the  internal  plantar  nerve  the 
two  internal,  muscles. 


THE    -MUSCULAR    SYSTEM.  165 

Third  Set. 

Flexor  Brevis  Hallucis  (m.  flexor  hallucis  obliquus).— 
Origin,  from  the  external  cuneiform  bone,  and  the  internal  bor- 
der of  the  cuboid  bone,  and  the  tendinous  expansion  of  the 
tibialis  posticus;  insertion,  into  the  first  phalanx  of  the  great 
toe  on  either  side;  action,  flexes  first  phalanx  of  great  toe; 
nerves,  the  internal  plantar  and  sometimes  a  branch  from  the 
external  plantar. 

Adductor  Hallucis. — Origin,  from  the  bases  of  the  sec- 
ond, third,  and  fourth  metatarsal  bones  and  from  the  sheath  of 
the  tendon  of  the  peroneus  longus;  insertion,  into  the  base  of 
the  first  phalanx  of  the  great  toe  on  the  outer  side;  nerve,  exter- 
nal plantar. 

Flexor  Brevis  Minimi  Digiti  (m.  flexor  digiti  quinti 
brevis). —Origin,  from  the  sheath  of  the  peroneus  longus  and 
the  base  of  the  metatarsal  bone  of  the  little  toe;  insert  ion,  into 
the  outer  side  of  the  base  of  the  little  toe;  nerve,  external 
plantar. 

Adductor  Transversus  Hallucis  (m.  transversus  pedis). 
— Origin,  from  the  inferior  metatarsophalangeal  ligaments  of 
the  three  outer  toes,  or  at  other  times  from  the  third  and  fourth, 
and  also  from  the  transverse  ligament  of  the  metatarsus;  inser- 
tion, into  the  outer  side  of  the  first  phalanx  of  the  great  toe; 
nerve,  external  plantar. 

Fourth  Set. 

Dorsal  Interossei  (m.  interossei  dorsal es). — Four  in 
number.  Origin,  by  two  heads  from  the  adjoining  bases  of,  the 
metatarsal  bones;  insertion,  into  the  bases  oi'  the  first  phalanges 
of  the  second,  third  and  fourth  toes,  the  second  having  two, 
one  on  either  side,  and  the  third  and  fourth  on  their  outer  side"; 
action,  abduct  the  toes  from  the  middle  line  of  the  second  toe' 
nerve,  external  plantar. 

PLANTAR  I\Ti:i;ossr;r  (m.  interossei  plan  tares). —Three  in 
number.  Origin,  from  the  bases  of  inner  side  of  the  third, 
fourth  and  fifth  metatarsal  bones;  insertion,  into  the  bases  of 
the  first  phalanges  on  the  same  side;  action,  adduct  the  toes 
toward  a  middle  line,  which  would  pass  through  the  sec.nd  toe- 
/"  rve,  the  external   plantar. 

The  Pasoias  (  Eascls). 

'I'Im'  fasciae  are  strong,  fibrous   (fibroareolar)    investments 

protecting  and  binding  together  l  he  muscles,  and  m  places  form- 


1(36  HUMAN    ANATOMY. 

ing  ligaments  and  intermuscular  septa.  They  consist,  for  the 
most  part,  of  two  layers,  a  superficial  and  a  deep. 

Fascias  of  the  Cranium  and  Face. — The  superficial  fas- 
cia of  the  head  and  face  is  everywhere  intimately  connected  to 
the  skin,  except  over  the  temporal  region,  where  it  forms  a  dis- 
tinct lamina,  inclosing  the  superficial  temporal  vessels  and  auric- 
ular muscles. 

The  deep  temporal  fascia  (fascia  temporalis)  is  a  dense, 
fibrous  membrane,  attached  to  the  margins  of  the  temporal  fossa 
and  zygoma,  and  from  which,  in  part,  the  temporal  muscle 
arises. 

Fascias  of  the  Neck. — The  superficial  fascia  is  continu- 
ous below  with  that  covering  the  pectoral  muscles  and  deltoid, 
and  blends  above  with  the  superficial  facial  muscles  and  fascia. 

The  deep  fascia  (fascia  colli)  adheres  below  to  the  clavicle 
and  sternum,  and  is  continuous  with  the  thoracic  fascia.  As  it 
ascends  the  neck  it  ensheathes  the  great  vessels  of  the  neck, 
sends  processes  to  the  larynx,  trachea,  pharynx  and  esophagus, 
and  above  ensheathes  the  submaxillary  and  parotid  glands,  and 
forms  the  stylomaxillary,  or  stylomandibular  ligament  (liga- 
mentum stylomandibular  e) . 

Fascias  of  the  Trunk. — The  superficial  fascia  may  con- 
sist of  two  or  more  layers  in  places.  It  is  continuous  above 
with  the  fascias  of  the  neck  and  upper  extremity,  and  below 
with  the  thigh.  Over  the  pectoral  region  the  mammary  glands 
are  inclosed  between  its  layers  (ligamenta  suspensoria)  ;  below 
the  level  of  the  umbilicus  it  again  divides  into  two  layers,  the 
superficial  of  which  is  continuous  with  the  superficial  layer  of 
the  superficial  fascia  in  the  thigh,  while  the  deep  layer  is 
attached  to  the  crest  of  the  ilium  and  Poupart's  ligament. 

The  deep  fascia  forms  intermuscular  septa  and  aponeuroses. 

The  lumbar  fascia  divides  into  three  layers,  inclosing  the 
quadratus  lumborum,  multifidus  spinas  and  erector  spina?  mus- 
cles, and  gives  attachment  to  the  internal  oblique  and  trans- 
versalis  muscles.  Its  anterior  and  middle  layers  are  attached 
to  the  transverse  processes,  and  its  posterior  layer  to  the  spinous 
processes.  Above,  its  anterior  layer  is  attached  to  the  lower  bor- 
der of  the  last  rib,  forming  the  ligamentum  arcuatum  externum 
'(arcus>  lumbocostalis  lateralis).  The  ligamentum  arcuatum  in- 
ternum (areas  lumbocostalis  medialis)  extends  from  the  body 
of  the  first  or  second  lumbar  vertebra  to  the  transverse  process, 
inclosing  the  psoas  magnus  muscle. 

Abdominal  and  Pelvic  Fascia. — The  transversalis  fascia 
is  a  thin  aponeurosis  between  the  peritoneum  and  transversalis 


THE    MUSCULAR    SYSTEM.  167 

muscle.  It  is  attached  below  to  the  pubes,  pectineal  line,  Pou- 
partfs  Ligament  and  the  femoral  vessels,  and  becomes  continu- 
ous with  the  iliac  and  pelvic  fascia.  The  pelvic  fascia  (fascia 
pelvis)  lines  the  pelvic  cavity  throughout,  attached  to  the  sym- 
physis pubis,  margin  of  obturator  foramen,  and  the  sacrum  and 
becomes  continuous  with  the  iliac  and  transversalis  fascias. 
[Below  it  forms  the  arcus  tendinece,  for  the  origin  of  muscles  and 
the  division  into  the  rectovesical  and  obturator  fascias  (vide 
Perineum). 

The  iliac  fascia  (fascia  iliaca)  is  a  thin,  fibrous  mem- 
brane investing  the  psoas  and  iliacus  muscles.  Above  it  is 
attached  to  the  Ligamentum  arcuatum  internum,  laterally,  with 
the  bodies  of  the  vertebras  and  sacrum,  and  below  it  is  attached 
to  Poupart's  ligament,  the  femoral  vessels,  pectineal  eminence, 
and  the  capsule  of  the  hip-joint. 

Upper  Extremity. — The  superficial  fascia  is  a  thin  mem- 
brane, inclosing  the  parts  throughout,  and  adherent  to  the  deep 
fascia  beneath. 

The  deep  fascia  is  very  dense  and  strong.  It  gives  off 
numerous  intermuscular  septa,  and  is  attached  to  the  olecranon 
and  back  part  of  ulna,  and  becomes  continuous  below  with  the 
anterior  and  posterior  annular  ligaments  of  the  wrist-joint,  both 
of  which  it  forms. 

The  anterior  annular  ligament  (ligamentum  carpi  trans- 
versum)  is  attached  to  the  ridge  of  the  trapezium,  the  tuberosity 
of  the  scaphoid,  the  unciform  process  of  the  unciform,  and  the 
pisiform  hone,  forming  a  strong,  iibrous  arch,  under  which  the 
flexor  tendons  of  the  lingers  pass. 

The  posterior  annular  ligament  (ligamentum-  carpi  dorsale) 
is  attached  to  the  radius,  ulna,  cuneiform  and  pisiform  hones, 
and  the  palmar  fascia,  forming  a  fibrous  arch  for  the  passage 
of  the  extensors  of  the  fingers. 

The  palmar  fascia  (aponeurosis  palmaris)  is  an  exceedingly 
dense,  triangular  mass  of  adipose  and  fibrous  tissue,  attached 

behind   to   the  anterior   annular   lip 'lit,  and    in  front  divides 

into  tour  fasiculi,  each  of  which  subdivides  into  two,  inserted 
into  the  lateral  ligaments  of  the  metacarpophalangeal  articula- 
tion-. These  digitatione  allow  the  passage  of  the  flexor  digi- 
toruni  tendons,  the  digital  vessels  and  nerves.  It  is  attached 
above  to  the  skin,  and  laterally  gives  off  vertical  septa,  which 
separate  the  middle  from  the  lateral  groups  of  palmar  muscles. 


168  HUMAN    ANATOMY. 


EASCTAS    OF    THE    LOWER    EXTREMITY. 

The  superficial  fascia-  resembles  that  in  other  localities, 
except  that,  in  the  front  of  the  thigh,  it  consists  of  two  or 
more  layers  between  which  are  found  the  superficial  vessels, 
nerves  and  lymphatic  glands.  The  under  layer  is  attached  to 
the  margins  of  the  saphenous  opening,  where  it  is  perforated  by 
numerous  lymphatic  vessels  and  blood-vessels ;  hence  its  name, 
cribriform  fascia  {fascia  cribrosa). 

The  deep  fascia  of  the  thigh,  or  fascia  lata,  is  a  dense 
fibrous  aponeurosis  attached  to  the  pubes,  Poupart's  ligament, 
crest  of  the  ilium,  sacrum  and  coccyx,  inclosing  the  gluteus 
maximus  and  tensor  vaginae  f  emoris  between  its  layers,  attached 
to  the  linea  aspera,  and  below  to  all  the  bony  points  about  the 
knee  joint,  being  attached  to  the  head  of  the  fibula  and  tuber- 
osities of  the  tibia  by  the  iliotibial  band  (trnctus  ilioiibialis 
[M  aissiati] ) . 

The  saphenous  opening  (fossa  ovalis)  is  a  large  opening  in 
the  fascia  lata  at  its  upper  and  inner  part  closed  by  the  crib- 
riform fascia.  Through  it  pass  the  internal  or  long  saphenous 
vein,  the  superficial  epigastric  and  external  pudic  arteries,  and 
lymphatics.  It  is  formed  by  the  iliac  and  pubic  portions  of  the 
fascia  lata.  The  iliac  portion  becomes  continuous  at  the  pec- 
tineal line  with  Gimbernat's  ligament,  and  its  free  border  forms 
the  falciform  border  (vide  Femoral  Hernia). 

The  pubic  portion  is  continuous  behind  the  femoral  vessels 
with  the  femoral  sheath  and  the  iliac  and  psoas  fascia.  At  the 
lower  border  of  the  saphenous  opening  it  is  continuous  with  the 
iliac  portion  of  the  fascia  lata. 

The  deep  fascia  of  the  leg  (fascia  cruris)  is  attached  above 
to  the  bony  points  about  the  knee,  continuous  with  the  fascia 
lata,  invests  the  leg  completely,  except  the  inner  surface  of  the 
tibia,  sends  in  a  deep  transverse  fascia  between  the  superficial 
and  deep  muscles  on  the  posterior  aspect  of  the  leg,  and  below 
becomes  continuous  with  the  annular  ligament  of  the  ankle- 
joint. 

The  annular  ligament  of  the  ankle  joint  consists  of  three 
portions — the  internal,  external  and  anterior.  It  is  attached 
to  the  bony  points  about  the  ankle  joint,  the  external  and  inter- 
nal malleoli,  surfaces  of  the  os  calcis,  and  allows  the  passage 
of  the  muscles  to  the  foot. 

The  dorsal  aponeurosis  of  the  foot  (fascia  dorsalis  pedis) 
covers  the  back  of  the  foot,  uniting  with  the  plantar  fascia  at 


THE    MUSCULAR    SYSTEM.  1G9 

the  sides,  and  terminating  anteriorly  at  the  heads  of  the  meta- 
tarsal hones. 

The  plantar  aponeurosis  (aponeurosis  plantaris)  consists  of 
three  portions,  a  central  and  two  lateral  portions. 

The  middle  portion  commences  at  the  inner  tubercle  of  the 
os  calcis  and  proceeds,  gradually  becoming  broader,  to  the  heads 
of  the  metatarsal  bones,  where  it  divides  into  four  branches, 
each  of  which  nearly  surrounds  the  corresponding  flexor  tendon 
to  which  it  gives  passage,  and  is  inserted  into  the  edges  of  the 
dorsal  expansion  of  the  first  phalanges. 

The  inner  portion  arises  from  the  internal  annular  liga- 
ment, covers  the  abductor  pollicis  muscle,  and  joins  the  dorsal 
aponeurosis  internally  and  the  internal  septum  externally. 

The  outer  portion,  much  stronger,  arises  from  the  os  calcis, 
covers  the  abductor  minimi  digiti  muscle,  and  joins  the  external 
plantar  septum  internally  and  dorsal  aponeurosis  externally,  and 
is  firmly  attached  to  the  base  of  the  fifth  metatarsal  bone. 

Numerous  septa  pass  from  the  upper  surface  of  the  plantar 
fascia  between  the  plantar  muscles  and  tendons  to  be  inserted 
into  the  metatarsal  and  tarsal  bones. 


THE  HEART  AND  VASCULAR  SYSTEM. 


The  pericaedium  is  a  conical,  membranous,  closed  sac, 
surrounding  the  heart  and  the  roots  of  the  great  vessels.  It 
occupies  the  greater  part  of  the  middle  mediastinum,  its  apex 
upward,  its  base  downward  and  attached  to  the  central  tendon 
of  the  diaphragm.  It  is  a  fibroserous  membrane,  consisting  of 
an  outer  fibrous  coat  and  an  inner  serous  coat.  The  latter  is 
composed  of  a  visceral  layer  (epicardvum)  reflected  over  the 
heart  and  vessels,  and  a  parietal  layer  lining  the  inner  surface 
of  the  fibrous  sac.    It  secretes  a  thin,  serous  fluid. 

The  fibrous  coat  becomes  continuous  above  with  the  deep 
layer  of  the  cervical  fascia,  being  prolonged  upward  on  the 
outer  surfaces  of  all  the  great  vessels,  except  the  inferior  vena 
cava. 

The  Heart  (Cor). 

The  heart  is  a  hollow,  muscular  organ,  placed  obliquely 
within  the  chest,  and  inclosed  within  the  pericardium.  Its  base 
(basis  cordis)  is  directed  upward  and  backward,  opposite  the 
fifth  to  eighth  dorsal  vertebrae;  its  apex  (apex  cordis)  down- 
ward to  the  left,  opposite  the  interspace  between  the  fifth  and 
sixth  costal  cartilages.  Its  weight  is  about  ten  to  twelve  ounces 
in  male,  eight  to  ten  in  female ;,  length  five  inches,  breadth  three 
and  a  half  inches,  thickness  two  and  a  half  inches. 

It  is  divided  into  four  parts : — 

Right  auricle,  Left  auricle, 

Right  ventricle,  Left  ventricle, 

an  auricle  and  ventricle  on  each  side.  This  division  is  indicated 
on  both  surfaces  of  the  organ  by  two  grooves  crossing  each  other 
and  named,  from  their  position,  the  longitudinal  or  the  inter- 
ventricular (sulci  longitudinalis) ,  the  transverse  or  the  auric- 
uloventricular  (sulcus  coronarius)  grooves. 

Eight  Auricle. — The  right  auricle  (atrium  dextrum) 
consists  of  two  portions — a  sinus  or  atrium  and  an  appendix 
auriculce,  which  projects  to  the  right  side  of  the  origin  of  the 
aorta.  The  walls  at  the  fore  and  outer  part  and  in  the  auricu- 
lar appendage  are  thickened  by  musculi  pectinati.     The  mus- 

(170) 


THE    HEART    AND    VASCULAR    SYSTEM. 


171 


cular  tissue  of  the  auricles  is  connected  with  that  of  the 
ventricles  by  a  small  band  of  fibers,  the  auriculoventricular 
fasciculus,  or  "bundle  of  His." 

This  smooth  ridge  is  known  inside  the  auricle  as  the  crista 
terminate  of  His,  and  outside  the  groove  is  called  the  sulcus 
terminalis  of  His.    Its  interior  presents  the  following  parts:— 

Openings  of  the  superior  and  inferior  vena'  cava',  neither 
of  which  are  protected  by  valves : 

Opening  of  coronary  sinus  {sinus  coronarius),  protected  by 
a  valve  of  two  unequal  segments— the  coronary  valve; 


Fig.  77. 

Right  side  of  heart:  a,  apex;  6,  right  ventricle;  d,  pulmonary 
artery;  e,  f,  chords  tendineas;  p,  aorta;  3,  superior  vena  cava;  5, 
inferior  vena  cava. 

Foramina  Thebesii    (foramina   vcnarum  minimarum),  mi- 
nute foramina  returning  the  blood  from  the  heart-muscle; 

stachiap  valve  (valvula  rcmr  n,r,r  info-ions  [Eu- 
rtachW]),  the  remainfi  of  a  fetal  structure,  extending  from  the 
right  Of  the  orifice  Of  the  inferior  vena  cava  to  the  outer  border 

of  the  oval  foramen  ; 

Fossa  oralis,  the  obliterated  foramen  ovale  of  fetal  lite: 
AnnuTui  ovalis  {limbus  fossm  oralis  |  VieussenU]) ,  the  oval 

margin  of  the  preceding  structure; 

Tubercle  of  Lower  (tuberculwn  intervenosum  \Lowen\),Q 

small   rudimental   projection   on   the   right    wall,   directing  the 

blood  toward   the  annciilo\eiit  ri.ular  opening; 


172  HUMAN    ANATOMY. 

Musculi  pectinati,  elevated  muscular  columns  before  re- 
ferred to; 

Auriculoventricular  opening  (ostium  venosum  dextrum), 
an  oval  aperture  about  one  inch  in  diameter,  surrounded  by  a 
fibrous  ring,  and  protected  by  the  tricuspid  valve. 

The  Left  Auricle  (atrium  sinistrum). — The  left  auricle 
is  smaller,  and  its  walls  somewhat  thicker  than  the  right,  and 
consists  of  a  cuboidal  sinus  and  an  elongated  appendix  auriculae. 
Its  interior  surface  is  smooth,  except  the  auricular  appendage, 
which  is  provided  with  musculi  pectinati,  and  presents  the  fol- 
lowing openings : — 

Pulmonary  veins,  four  in  number,  two  on  either  side;  they 
are  without  valves; 

Auriculoventricular  opening  (ostium  venosum  ventriculi 
sinistri),  an  oval  aperture,  rather  smaller  than  the  right,  and 
protected  by  the  bicuspid  or  mitral  valve. 

The  Eight  Ventricle  (ventriculus  dexter). — The  right 
ventricle  is  triangular,  with  thick  walls  (one-quarter  inch),  and 
occupies  the  anterior  part  of  the  organ.  Its  capacity  is  about 
three  fluidounces.    It  presents  the  following: — 

Infundibulum  (conus  arteriosus),  a  conical  pouch,  from 
which  the  pulmonary  artery  arises ; 

Columnse  carneae  (trabecular  carnece),  muscular  columns 
projecting  from  the  inner  surface,  three  or  four  of  which  (mus- 
culi papillares)  give  attachment  to  the  chordae  tendineae; 

Chordce  tendinew,  delicate  tendinous  cords,  connecting  the 
margins  and  central  portions  of  the  tricuspid  valve  with  the 
columns  carneae; 

Tricuspid  valve  (valvula  tricuspidalis) ,  consists  of  three 
segments  or  cusps  (cuspides)  which  consist  of  triangular  dupli- 
cations of  endocardium,  strengthened  by  fibrous  tissue;  they  are 
attached  by  their  bases  to  the  auriculoventricular  orifice  (an- 
nulus  fibrosis  dexter)  and  their  free  margins  give  attachment  to 
the  chordae  tendineae  (ostium  venosum  ventriculi  dextri). 

Semilunar  valves  (valvular  sem.ilunares  a.  pvlmonalis)  con- 
sist of  three  semicircular  folds,  guarding  the  orifice  of  the  pul- 
monary artery;  their  free  margins  are  thickened  by  nodules,  the 
corpora  Arantii   (nodulus  valvules  semilunaris  [Arantii~\)  ; 

Opening  of  the  pulmonary  artery  (ostium-  arteriosum) ,  at 
the  apex  of  the  conus  arteriosus,  is  circular  in  outline  and  pro- 
tected by  the  semilunar  valves; 

Sinuses  of  Valsalva^  three  pouches,  situated  one  behind  each 
semilunar  valve. 


THE    HEART    AND    VASCULAR    SYSTEM.  173 

The  Left  Ventricle  (ventricutus  sinister). — The  left 
ventricle  is  longer,  more  conical,  and  its  walls  three  times  as 
thick  a<  the  right.  It  forms  the  apex  {apex  cordis)  and  most 
of  the  posterior  and  inferior  (facies  diaphragmatica)  portion  of 
the  heart.  It  presents  the  following  parts  in  its  interior  :— 
Col  urn  iter  carnece,  and 

Chorda  tendinece,  much  the  same  as  the  right;  _ 

Uiriculoventricular  opening  {ostium  venosum  ventnculi 
sinistri),  a  little  smaller  than  the  corresponding  orifice  on  the 
right  side,  similarly  formed,  and  protected  by  the  mitral  valve; 
'  The  mitral  valve  {valvula  bicusptdalis)  consists  of  two 
unequal  segments,  attached  the  same  as  the  tricuspid,  and  also 
affording  attachment  to  the  chordae  tendmese; 

Aortic  opening  {ostium  arteriosum),  a  circular  opening  to 
the  right  of  the  auriculoventricular  opening; 

The  semilunar  valves  {valvule  semilunares  aorta'),  three 
in  number,  surround  the  aorta,  and  are  larger  and  stronger  than 
those  on  the  right  side ;  . 

Sinus  aortici  (sinuses  of  Valsalva)  are  depressions  situated 

behind  each  valve.  .  „ 

Structure  of  the  Heart. — The  heart  is  composed  01 
finely  striated  muscular  walls,  with  external  serous  covering 
from  the  pericardium  and  internal  serous  lining  the  endo- 
cardium the  latter  continuous  with  that  of  blood  vessels.  The 
endocardium  is  a  thin,  translucent  membrane,  consisting  ot 
endothelium  and  a  fine  basement  membrane,  beneath  which  is 
a  fibrocystic  layer.  The  doublings  of  these  layers  constitute  the 
valve<  The  tricuspid  and  mitral  valves,  as  well  as  the  aortic 
and  pulmonary,  are  surrounded  by  a  fibroelastic  ring  {annulus 
fibrosa),  which  furnishes  a  "puctum  fixuur  for  the  varying 
musculature  of  the  heart.  .  . 

The  muscular  structure  consists  of  an  intricate  interlace- 
ment of  fibrous  Lands.  Of  these  there  are  two  groups— those 
of  the  auricles  and  those  of  the  ventricles. 

The  former  consist  of  a  superficial  transverse  set  and  the 
internal  or  deep  set,  of  which  there  are  the  looped  and  the 
circular. 

The  fibers  of  the  ventricles  consist  of  seven  layers  m  a  gen- 
era]  oblique  and  circular  manner,  ami  terminating  in  a  whorl 
,„.  ,.,„•/,,,.  a1  the  apex,  some  of  the  abers  fern, mating  m  the 
oolumnse  carnese,  musculi  pectinati,  while  others  ascend,  torm- 
ina i„  their  course  a  twisted  loop  like  the  figure  s.  The  arteries 
of  the  Lean  are  i he  ri-ht  and  left  coronarv.  The  veins  are  the 
anterior  or  great,  middle  <>r  posterior  cardiac,  the  left  auricular, 


174  HUMAN    ANATOMY. 

the  right  auricular  and  venge  Thebesii.  The  lymphatics  end  in 
thoracic  and  right  lymphatic  ducts.  The  nerves  are  derived 
from  the  cardiac  plexus  of  pneumogastric,  spinal  and  great 
sympathetic. 

The  Vascular   System. 

The  vascular  system  consists  of  four  sets  of  vessels — ar- 
teries, capillaries,  veins  and  lymphatics.  Anastomoses  are 
common. 

The  vessels  that  convey  blood  to  and  from  the  tissues  of 
the  body  generally  constitute  the  general  system. 

Those  that  carry  blood  to  and  from  the  lungs  form  the 
pulmonary  system. 

The  vessels  passing  to  the  liver  form  the  portal  system. 

The  arteries,  for  the  most  part,  are  composed  of  three 
coats : — 

Tunica  adventitia,  or  external  coat,  consists  of  fibrous  tis- 
sue, thinnest  on  the  largest  trunks,  and  disappears  in  those 
which  merge  into  capillaries. 

The  tunica  media,,  or  middle  coat,  is  thickest  in  the  large 
trunks,  and  consists  mainly  of  elastic  tissue,  together  with  some 
unstriated  muscle  and  some  connective  tissue;  in  smallest  arter- 
ies it  consists  alone  of  muscular  tissue. 

The  tunica  intima,  or  internal  coat,  thinnest,  most  trans- 
parent and  elastic,  is  composed  of  lining  endothelium,  basement 
membrane,  and  layers  of  elastic  tissue.  The  elastic  tissue  in 
layers  forms  nets,  constituting  so-called  perforated  or  fenestrated 
membrane.  It  becomes  continuous  with  capillaries.  The  walls 
of  larger  arteries  are  supplied  by  blood  vessels  from  neighboring 
arteries.  Nutrient  arteries  form  a  network  of  capillaries,  and 
returning  veins  empty  into  contiguous  veins.  The  nerves  are 
both  medullated  and  non-medullated  and  chiefly  pass  to  the 
muscle-fibers. 

Arteries  dilate  and  contract  with  the  action  of  the  heart, 
constituting  the  ptdse. 

The  veins. — Larger,  more  numerous,  and  more  capacious 
than  the  arteries,  with  one  exception  (the  portal  vein)  they 
convey  blood  to  the  heart.  The  large  veins  emptying  into  the 
heart  are : — 

Four  pulmonary ; 

Superior  and  inferior  vense  cavse; 

Coronary  veins  from  walls  of  the  heart  through  the  coronary 
sinus. 


THE    HEART    AND    VASCULAR    SYSTEM.  175 

The  larger  arteries  have,  each,  one  companion  vein,  the 
medium  arteries  two.  In  some  positions  they  form  venous 
plexuses,  corresponding  to  arterial  anastomoses. 

Many  large  veins  have  valves,  usually  in  pairs,  attached  by 
convex  border. 

There  are,  however,  no  valves  in  the  pulmonary,  superior 
and  inferior  cavae,  azygos,  portal  vein  and  branches,  hepatic, 
renal,  uterine,  and  spinal,  and  most  of  those  of  head  or  neck. 

In  certain  membranes  and  organs  channels  exist,  lined  by 
internal  coat  of  blood  vessel,  termed  venous  sinuses,  as  in  the 
dura  mater,  bones  and  uterus. 

The  coats  of  the  veins  are  similar  to  those  of  the  arteries. 
and  differ  chiefly  in  the  weakness  of  the  middle  or  muscular 
coat,  which  allows  them  to  remain  open. 

The  external  fibrous  coat  has  also  longitudinal,  unstnated 
muscular  tissue  in  veins  of  abdominal  cavity: — 

The  middle,  unstriated  muscular  and  fibrous  tissue; 
The  internal,  no  fenestrated  membrane. 
The  walls  have  nutritive  vessels,  and  are  well  supplied  with 
non-medullated  and  medullated  nerves,  which  pass  to  the  mus- 
cular coat.  _         , 

Both  arteries  and  veins  are  insensitive  m  healthy 
Tin:  capillaries  communicate  with  the  terminations  of 
the  arteries  and  veins,  and  do  not  communicate  with  tissue 
proper  which  is  supplied  by  imbibition.  They  vary  in  size  in 
different  organs  from  y2ooo  to  Vsooo  inch  in  diameter,  but  all 
permit  the  passage  of  blood  corpuscles.  Their  form  is  depend- 
ent on  the  form  of  tissue  supplied. 

Composition  of  the  Blood. — Blood  within  the  vessels  is 
a  perfect  fluid,  alkaline  reaction,  saline  taste,  average  specific 
gravity  1060,  and  of  feeble,  peculiar  odor.  Within  the  arterial 
jselfl  it  is  bright  red  in  color,  becoming  in  the  veins  (partic- 
ularly the  venae  portae  and  pulmonary  arteries)  a  deep  maroon 
or  reddish-black  color. 

It  constitutes  about  Vi -  or  1/u  of  the  body-weight,  an. I  con- 
sists <-f  the  Liquor  sanguinis  and  the  corpuscles,  red,  white,  etc. 
The  red  corpuscles  or  erythrocytes  are  elastic,  specific 
gravity  L088,  Don-nucleated,  and  average  about  Hooo  "M  "' 
diameter.  A  cubic  millimeter  of  blood  contains,  m  the  male. 
5,000,000  red  blood-cells,  and,  in  the  female,  4,500,000.  On 
evaporation  they  become  stellate,  and  swell  up  with  water.  They 
vary  much  in  size  and  Bhape  in  differenl  animals,  and  contain 
hemoglobin,  which  carries  oxygen  to  the  tissues  an. I  C02  to  the 
bin. 


Clot. 


176  HUMAN    ANATOMY. 

The  colorless  corpuscles  or  leucocytes  are  free  nucleated 
protoplasmic  masses,  capable  of  ameboid  movement.  They  con- 
tain fat-corpuscles,  myosin,  cholesterin,  protagon,  glycogen  and 
nuclein.  There  is  about  1  white  corpuscle  to  every  600  red 
corpuscles,  or  in  1  cubic  millimeter  of  blood  there  are  present 
about  from  5000  to  10,000  white  corpuscles,  an  average  of  7500. 
According  to  Ehrlich  and  others,  by  means  of  a  "tri-acid  stain," 
five  varieties  of  colorless  cells  may  be  distinguished  as  fol- 
lows : — 

1.  Small  lymphocytes, 

2.  Large  lymphocytes  or  mononuclear  leucocytes, 

3.  Transitional  leucocytes, 

4.  Polymorphonuclear  leucocytes,  and 

5.  Eosinophiles. 

The  liquor  sanguinis  is  a  pale,  amber-colored  fluid,  holding 
the  corpuscles  in  suspension,  and  very  prone  to  coagulate.  The 
coagulation  of  the  blood  results  in  the  formation  of  a  clot,  or 
crassamentum,  and  the  serum,  in  the  following  manner : — 

C  Cornuscles      /  White  corPuscles 
corpuscles,     j  Red  corpuacle8- 

Fluid  blood   J  ,,, 

I  P1fsma°r  1  Fibrin. 

!  eLl(luor  \  Serum.  J-Q 

i  Sanguinis  J  berum. 

THE    CIRCULATION    OP    THE    BLOOD. 

Fetal  Circulation. — The  fresh  arterial  blood  returning  from 
the  placenta  through  the  umbilical  vein  enters  the  fetus  at  the 
umbilicus,  passes  along  the  suspensory  ligament  to  the  under 
surface  of  the  liver,  where  a  portion  passes  directly  into  the 
inferior  vena  cava  by  the  junction  of  the  ductus  venosus  with 
the  left  hepatic  vein,  a  portion  enters  the  liver  and  reaches  the 
inferior  vena  cava  through  the  hepatic  veins,  and  the  larger  por- 
tion mixes  with  the  portal  venous  blood  before  reaching  the  vena 
cava  through  the  hepatic  veins.  It  ascends  in  the  inferior  vena 
cava  along  with  the  venous  blood  from  the  trunk  and  lower 
extremities  to  enter  the  right  auricle  of  the  heart  (Fig.  78). 
Here  it  is  directed  by  the  Eustachian  valve  through  the  foramen 
ovale  into  the  left  auricle,  into  the  left  ventricle,  and  so  through 
the  aorta,  chiefly  to  the  head  and  upper  extremities,  a  small  por- 
tion only  entering  the  descending  aorta.  It  is  returned  by  the 
superior  vena  cava  to  the  right  auricle,  passes  over  the  Eu- 
stachian valve  to  the  right  ventricle,  and  so  through  the  pulmo- 
nary artery  toward  the  lungs,   but    (the  lungs  being  almost 


THE    HEART    AND    VASCULAR    SYSTEM. 


177 


Fig.  78. 

Diagram  of  the  fetal  circulation:  1,  umbilical  cord,  with  veins  and  arteries; 
2,  placenta;  :',  divisions  of  umbilical  vein;  4,  hepatic  branches;  5,  ductus 
venosus;  6.  inferior  vena  cava;  7,  portal  vein;  8,  right  auricle;  9,  left  auricle; 
10,  left  ventricle;  11,  arch  of  aorta;  14,  superior  vena  cava;  15,  right  ventricle; 
10,  pulmonary  artery;  17,  ductus  arteriosus;  18,  descending  aorta;  19,  umbilical 
arteries. 


12 


178  HUMAN    ANATOMY. 

impervious)  most  of  it  passes  through  the  ductus  arteriosus  into 
the  descending  aorta  (mixing  with  the  small  quantity  from  the 
left  ventricle  before  mentioned)  to  supply  the  lower  extremities, 
abdominal  and  pelvic  viscera,  and  as  venous  blood  to  return 
through  the  umbilical  arteries  to  the  placenta. 

Circulation  After  Birth  and  in  Adult. — The  dark  venous 
blood  from  the  entire  body  is  received  through  the  superior  and 
inferior  venae  cavse  and  coronary  sinus  into  the  right  auricle, 
whence  it  passes  into  the  right  ventricle,  to  be  sent  through 
the  pulmonary  artery  into  the  lungs.  Here  it  becomes  oxygen- 
ated, and  as  bright  arterial  blood  it  returns  to  the  left  auricle 
by  the  pulmonary  veins,  and  passes  into  the  left  ventricle, 
whence  it  is  distributed  through  the  aorta  and  its  branches  to 
the  entire  body. 

AORTA    (ARTERIA    MAGNA )  . 

This  is  the  main  trunk  of  the  systemic  arteries.  Com- 
mencing at  the  upper  part  of  the  left  ventricle,  it  ascends  for 
a  short  distance,  arches  backward  over  the  right  pulmonary 
artery,  the  root  of  the  left  lung,  to  the  left  side  of  the  body  of 
the  fourth  dorsal  vertebra,  where  it  passes  downward  through 
the  diaphragm  and  becomes  the  abdominal  aorta.  It  then 
descends  to  the  lower  border  of  the  fourth  lumbar  vertebra, 
where  it  terminates  by  dividing  into  the  left  and  right  common 
iliac  arteries.  In  its  course  it  is  divided  into  the  arch,  the 
thoracic  aorta,  and  the  abdominal  aorta,  the  arch  being  sub- 
divided into  the  ascending,  transverse  and  descending  portion. 

Relations. — The  ascending  portion  of  the  arch  is  in  relation  on  the 
right  side  with  the  superior  cava  and  right  auricle;  on  the  left  side 
with  the  pulmonary  artery;  in  front,  with  the  pulmonary  artery,  the 
pericardium,  the  right  appendix  auriculae  and  the  thymus  gland;  and 
behind,  with  the  root  of  the  right  lung  and  the  right  pulmonary  vessels. 

The  transverse  portion  of  the  arch  is  in  relation  in  front  with  the 
left  lung  and  pleura,  the  left  pneumogastric  and  phrenic  nerves,  the 
superficial  cardiac  nerves,  the  left  superior  intercostal  vein,  and  the 
thymus  gland;  behind,  with  the  trachea,  the  esophagus,  the  thoracic 
duct,  the  deep  cardiac  plexus,  and  the  left  recurrent  nerve;  above,  with 
the  arteria  innominata,  the  left  innominate  vein,  the  left  subclavian, 
and  the  left  carotid;  and  below,  with  the  left  bronchus,  the  bifurcation 
of  the  pulmonary  artery,  the  left  recurrent  nerve,  and  the  remains  of 
the  ductus  arteriosus. 

The  descending  portion  of  the  arch  is  in  relation  in  front  with  the 
root  of  the  left  lung  and  the  pleura ;  behind,  with  the  left  side  of  the 
body  of  the  fifth  dorsal  vertebra;  on  the  right  side  with  the  thoracic 
duct  and  esophagus;   and  on  the  left  side  with  the  pleura. 


THE    HEART    AND    VASCULAE    SYSTEM.  179 

The  branches  of  the  aorta  are,  from  the  arch: — 

Two  coronary,  Left  common  carotid. 

Innominate,  Left  subclavian. 

The  coronary  arteries  supply  the  heart  and  are  two  in 
number — the  right  and  the  left  (a.  coronaria  cordis  dextra  et 

sinistra).  The  right  arises  from  the  aorta,  above  the  right  semi- 
lunar valve,  and  passes  downward  in  a  groove  between  the  right 
auricle  and  ventricle  on  its  posterior  surface,  dividing  into  two 
branches,  one  of  which  anastomoses  with  the  left  coronary.  The 
left  coronary  arises  above  the  left  semilunar  valve  and  descends 
in  the  anterior  interventricular  groove,  where  it  divides  into 
two  branches,  one  of  which  anastomoses  with  the  right  coronary. 
Arteria  Innominata  (a.  anonyma). — This  is  the  largest 
branch  from  the  arch  of  the  aorta.  It  ascends  to  the  upper 
border  of  the  right  sternoclavicular  articulation,  where  it  divides, 
into  the  right  common  carotid  and  the  right  subclavian  arteries. 
It  is  a  short  vessel,  from  one  and  a  half  to  two  inches  long. 

Relations. — It  is  in  relation  in  front  with  the  sternum,  the  sterno- 
hyoid and  sternothyroid  muscles,  the  left  innominate  and  right  inferior 
thyroid  veins,  the  thymus  gland,  and  the  cardiac  branch  from  the  right 
pneumogastric ;  behind,  with  the  trachea;  on  the  right  side,  with  the 
pleura  and  right  vena  innominata  and  right  pneumogastric  nerve;  on 
the  left  side,  with  the  left  carotid  and  the  thymus  gland. 

The  Common  Carotid  Arteeies  (a.  carotis  communis) . — 
The  left  common  carotid,  arising  directly  from  the  arch  of  the 
aorta,  is  longer  and  ascends  more  obliquely  and  is  more  deeply 
placed  than  the  right. 

From  the  sternoclavicular  articulation  to  their  division  at 
the  upper  border  of  the  thyroid  cartilage  the  common  carotid  on 
either  side  pursues  the  same  course.  At  the  lower  part  of  the 
neck  the  two  vessels  are  separated  by  a  very  short  interval, 
which  is  occupied  by  the  trachea,  but  at  the  upper  part  they 
diverge  widely;  the  larynx,  pharynx,  thyroid  body,  and  several 
muscles  being  interposed  between  them.  It  ascends  the  neck  in 
a  direction  indicated  by  a  line  drawn  from  the  sternoclavicular 
articulation  to  midway  between  the  mastoid  process  and  the 
angle  of  the  lower  jaw. 

Relations.  —It    is    in    relation    in    front    with    the    sternomastoid, 

sternothyroid,  sternohyoid  and  omohyoid   scles,  the  anterior  jugular 

and  the  superior  ami  middle  thyroid  veins,  the  sternohyoid  artery,  and 
the  descendens  and  communicans  noni  nerves;  behind  ii  rests  upon  the 
longus  colli  and  rectus  e;i|>iii>  anticus  major  muscles  and  is  in  relation 
with  the  sympathetic  nerve,  the  recurrent  laryngeal  nerve,  and  the 
inferior  thyroid  artery;  on  the  Outer  side,  with  the  pneumogastric  and 


180  HUMAN    ANATOMY. 

the  internal  jugular  vein;  to  the  inner  side,  the  larynx,  trachea,  pharynx, 
thyroid  gland,  inferior  thyroid  artery  and  the  recurrent  laryngeal 
nerve. 

THE    EXTERNAL    CAROTID    ARTERY     (A.     CAROTIS    EXTERNA). 

From  its  commencement  at  the  superior  border  of  the  thy- 
roid cartilage  it  passes  upward  and  forward  and  then  backward, 
beneath  the  anterior  margin  of  the  sternomastoid  muscle,  in  a 
direction  indicated  by  an  imaginary  line  drawn  from  the  supe- 
rior border  of  the  thyroid  cartilage  to  a  point  midway  between 
the  meatus  and  the  neck  of  the  condyle  of  the  lower  jaw.  It 
ascends  through  the  space  known  as  the  superior  triangle  of  the 
neck. 

Relations. — It  is  in  relation  in  front  with  the  parotid  gland  and 
the  facial  nerve  and  tempo romaxillary  vein  passing  through  it,  covered 
by  the  skin,  superficial  fascia,  platysma,  and  deep  fascia,  and  is  crossed 
by  the  digastric  and  stylohyoid  muscles,  hypoglossal  nerve,  lingual  and 
facial  veins;  behind  it  is  separated  from  the  internal  carotid  by  the 
parotid  gland,  styloglossus  and  stylopharyngeus  muscles,  and  the  glosso- 
pharyngeal nerve,  and  at  its  lower  part  the  superior  laryngeal  nerve 
ascends  behind  it;  to  its  inner  side  it  is  in  relation  with  the  pharynx, 
hyoid  bone,  superior  laryngeal  nerve,  and  the  ramus  of  the  lower  jaw, 
from  which  it  is  separated  by  the  parotid  gland. 

The  branches  of  the  external  carotid  are  eight: — 

1.  Superior  thyroid,  5.  Posterior  auricular, 

2.  Lingual,  6.  Ascending  pharyngeal, 

3.  Facial,  7.  Temporal, 

4.  Occipital,  8.  Internal  maxillary. 

1.  Superior  thyroid  (a.  thyreoidea  superior)  arises  below 
the  great  cornu  of  the  hyoid  bone,  passes  beneath  the  sterno- 
hyoid, omohyoid  and  sternothyroid  muscles  to  the  upper  part 
of  the  thyroid  gland,  where  its  terminal  branches  anastomose 
with  its  fellow  of  the  opposite  side.    Its  branches  are : — 

(a)  Hyoid  (ramus  hyoideus) ,  to  the  lower  border  of  the  hyoid 
bone ; 

(b)  Superficial  descending  branch  {ramus  sternocleidomastoideus) , 
crosses  the  common  carotid  artery  to  supply  the  skin  and  sternomas- 
toid muscle; 

(c)  Superior  laryngeal  (a.  laryngea  superior),  passes  beneath  the 
thyrohyoid  muscle  with  the  superior  laryngeal  nerve; 

(d)  Cricothyroid  (ramus  cricothyreoideus) ,  crosses  the  crico- 
thyroid membrane. 

2.  The  lingual  artery  (a.  lin gualis)  arises  from  the  ante- 
rior part  of  the  external  carotid,  between  the  superior  thyroid 
and  the  facial.     It  passes  inward  and  upward  to  the  greater 


THE    HEART    AND    VASCULAR    SYSTEM.  181 

cornu  of  the  hyoid  bone,  and,  descending,  reaches  the  under 
surface  of  the  tongue  and  runs  along  its  under  surface  as  far 
as  its  tip,  where  it  terminates  as  the  ranine. 

In  its  course  it  passes  through  a  triangle  hounded  on  two 
sides  below  by  the  two  bellies  of  the  digastric,  and  above  by  the 
hypoglossal  nerve,  passing  under  the  hyoglossus  muscle.  Its 
branches  are : — 

Hyoid   (ramus  hyoideus) ,  to  the  hyoid  bone; 

Dorsalis  linguae  (ramus  darsalis  Ungucc),  supplies  the  epiglottis, 
soft  palate,  tonsil,  and  the  mucous  membrane  of  tongue; 

Sublingual  (a.  sublingualis),  supplies  mylohyoid  and  geniohyo- 
glossus  muscles  and  sublingual  gland; 

Ranine  (a.  profunda,  lingua'),  the  terminal  branch,  ends  at  the 
tip  of  the  tongue. 

3.  The  facial  artery  (a.  ma.villaris  externa)  arises  from 
the  anterior  portion  of  the  external  carotid  artery  above  the 
lingual.  It  ascends  forward  through  the  submaxillary  gland, 
crosses  the  lower  jaw  at  the  anterior  border  of  the  masseter 
muscle,  and  crosses  the  cheek  to  the  angle  of  the  mouth  and 
the  side  of  the  nose,  where  it  terminates  as  the  angular  artery 
(a.  angularis).    Its  branches  in  the  neck  are: — 

Inferior  or  ascending  palatine  (a.  palatine  ascendens) ,  supplies 
the  soft   palate,   palatine  glands,  tonsil   and   Eustachian   tube; 

Tonsillar  (ramus  tonsillaris),  supplies  the  root  of  the  tongue 
and  tonsil; 

Submaxillary  {rami  glandular  es) ,  supplies  the  submaxillary 
gland  and  neighboring  lymphatics,  muscles,  and  skin; 

Submental  [a.  submentalis ) ,  supplies  the  chin,  lower  lip  and 
neighboring  structures; 

Muscular,  to  the  buccinator,  masseter  and  internal  pterygoid 
muscles. 

In  the  face: — 

Muscular,  to  the  same  muscles  as  given  above; 

Inferior  labial    (a.  labiaMs  inferior),  to  the  skin  of  the  lower  lip; 

Inferior  coronary,  to  the  mucous  membrane,  muscles  and  glands 
of  the  lower  lip; 

Superior  coronary  (a.  labialis  superior),  to  the  structures  of  the 
Upper   lip  and  nasal   septum; 

Lateralis  nasi,  to  the  skin  of  the  nostrils,  anastomoses  with  the 
nasal  branch  of  ophthalmic; 

Angular  I",  angularis),  supplies  lachrymal  sac  and  skin.  All  of 
these  branches  anastomose  freely  with  the  neighboring  arteries. 

4.  The  occipital  artehy  (a.  arteria  occipitalis)  arises 
from  the  posterior  portion  of  the  external  carotid,  about  tin' 
lower  border  of  the  digastric  muscle.  It  passes  beneath  the 
stylohyoid  muscle,  the  digastric  muscle,  and  part  of  the  parotid 


182 


HUMAN    ANATOMY. 


gland,  and,  ascending,  grooves  the  internal  surface  of  the  mas- 
toid portion  of  the  temporal  bone  and  distributes  itself  over  the 
occiput  as  high  as  the  vertex.     Its  branches  are : — 

Muscular    (rami    musculares) ,   to    splenius,    digastric,    stylohyoid, 
etc; 

Sternomastoid    (a.  stemocleidomastoidea) ,  crosses  the  hypoglossal 
to   the   sternomastoid  muscle; 

Auricular    (ramus   auricularis) ,   is   distributed   to   the  back   part 
of  the  concha; 

12      10 


Pig.  79. 


Arteries  of  face  and  head:  1,  common  carotid;  2,  internal  carotid; 
3,  external  carotid;  4,  occipital;  5,  superior  thyroid;  7,  lingual;  9, 
facial;  10,  temporal;  11,  submental;  12,  transverse  facial;  13,  infe- 
rior labial;  15,  17,  inferior  and  superior  coronary;  19,  lateral  nasal; 
21,   angular. 

Meningeal  (ramus  meningeus) ,  passes  through  the  foramen 
lacerum  posterius  to  the  dura  mater; 

Arteria  princeps  cervicis  ( ramus  descendens ) .  Its  superficial 
branch  anastomoses  with  the  superficial  cervical,  and  its  deep  branch 
with  the  deep  cervical  branch  from  the  superor  intercostal. 


THE    HEART    AND    VASCULAB    SYSTEM.  ^3 

Cranial  branches  are  distributed  to  the  scalp  over  the 
occiput. 

5.  The  posterior  auricular  artery  (a.  auric ularis  pos- 
terior) arises  from  the  posterior  portion  of  the  external  carotid, 
on  a  level  with  the  apex  of  the  styloid  process.  It  ascends 
beneath  the  parotid  gland  to  a  point  between  the  mastoid  process 
and  the  cartilage  of  the  ear,  where  it  divides  into  two  branches, 
one  going  to  the  ear  and  the  other  to  the  occiput.  Its  branches 
are: — 

Stylomastoid  (a.  stylomasioidea) ,  supplies  the  mastoid  cells, 
tympanum  and  semicircular  canals,  entering  the  cranium  through  the 
stylomastoid   foramen; 

Auricular  (ramus  am  inilaris ) ,  supplies  the  cartilage  of  the  ear; 

Muscular,  supply  the  sternomastoid,  digastric  and  stylohyoid 
muscles; 

Glandular,  to  parotid  gland. 

C.    The  ASCENDING   PHARYNGEAL  ARTERY    (a.  pharyngea  OS- 

cendens)  arises  about  the  commencement  of  the  external  carotid 
artery  and  ascends  to  the  base  of  the  skull  upon  the  rectus 
capitis  antieus  major.     Its  branches  are: — 

Pharyngeal  (rami  pharyngei),  supplies  the  three  constrictors  of 
the  pharynx  and  the  stylopharyngeus  muscles; 

External,  to  the  neighboring  muscles,  glands,  and  hypoglossal  and 
pneumogastric  nerves; 

Meningeal,  enter  the  skull  through  the  posterior  and  middle  lacer- 
ated foramina  and  the  anterior  condyloid  foramen. 

7.  The  superficial  temporal  artery  (a.  temporalis  su- 
perficialis)  is  the  smaller  of  the  two  terminal  branches.  It 
arises  in  the  parotid  gland,  crosses  the  root  of  the  zvgoma, 
ascends  forward  a  couple  of  inches,  and  divides  into  the  anterior 
temporal  and  the  posterior  temporal.     Its  branches  are: — 

Transverse  facial  (a.  transversa  faciei),  supplies  the  masseter 
muscle,  parotid  gland  and  skin; 

Middle  temporal  (a.  temporalis  media),  crosses  the  face  to  supply 
the  temporal  muscle  and  fascia; 

Anterior  auricular  (rami  auriculwres  anteriorcs) ,  supplies  the 
lobule,   external   meatus  and  front  part   of   pinna. 

The  ENTEENAL  maxillary  (a.  maxillaris  in  tenia)  is  the 
larger  of  the  two  terminal  branches  of  the  external  carotid.  It 
arises  in  the  parotid  gland  about  the  level  of  the  lower  part  of 
the  lobe  of  the  car.  passing  close  to  the  inner  side  of  the  m 
of  the  condyle  of  the  lower  jaw  to  be  distributed  to  the  deep 
structures  of  the  face.  Its  course  is  divided  into  three  portions: 
the  maxillary  portion,  passing  inward  and  forward  between  the 


184 


HUMAN    ANATOMY. 


internal  lateral  ligament  and  the  ramus  of  the  jaw;  the  ptery- 
goid portion,  passing  upward  and  forward  upon  the  external 
pterygoid  muscle;  and  the  third  part,  or  sphenomaxillary,  enters 
the  sphenomaxillary  fossa.  Its  branches  are,  from  the  maxillary 
portion : — 

Tympanic  (anterior)  (a.  tympanica  anterior),  supplies  the  tym- 
panum through  the  Glaserian  fissure,  forming  a  capillary  plexus  on  the 
tympanic  membrane; 

Middle  meningeal  ( a.  meningea  media ) ,  enters  the  cranium 
through  the  foramen  spinosum,  supplies  the  dura  mater,  and  gives  off 


Fig.  80. 

Internal   maxillary   artery:     A,    third   portion;    B,    second   portion;    C, 
first  portilon. 

a  petrosal  branch  (ramus  petrosus  super  ficialis)  to  facial  nerve  in 
hiatus  Fallopii; 

Small  meningeal  (ramus  meningeus  accessorius) ,  or  meningea 
parva,  enters  foramen  ovale  to  supply  dura  mater  and  Gasserian 
ganglion ; 

Inferior  dental  (a.  alveolaris  inferior),  accompanies  the  dental 
nerve  through  the  inferior  dental  canal  to  the  mental  foramen,  supply- 
ing the  jawbone,  teeth,  chin  and  mouth. 


The  pterygoid  portion : — 

Deep   temporal    (aa.    temporalis   profunda   anterior   et   posterior), 
supply  the  temporal  muscle; 

Pterygoid    (rami  pterygoidei) ,  to  pterygoid  muscles; 
Masseteric    (a.  masseterica) ,  to  the  masseter  muscle; 
Buccal    (a.  ljuccinatoria) ,  to  the  buccinator  muscle. 


POSTEROMEDIAN  GANGLIONIC 

POSTERIOR  TEM1VRAI 
ANTERIOR  TEMPORAL 
SUPERFICIAL  TEMPORAL 
ANTERIOR   AURICULAS 
MIDDLE  TEMPORAL 
ORBITAL 


Po-TERIOR  AURICULAR 
INTERNAL  MAXILLARY 
ARTERU  PRINCEPS  CERV1CIS 
OCCIPITAL 
SUP  BR.  PRINCEPS  CERVICIS' 
DEEP  BR.  PRINCEPS  CERVICIS 
ASCENDING  CERVICAL 
DEEP  CERVICAL 
SUPERFICIAL  CERVICAL 
SUPRASCAPULAR 
R.  SUBCLAVIAN 
POST    SCAPULAF 


SUP  \  ENA  CAVA 

B.  PULMONARY  A 
R    I'l  I.MONARV  VEIN 
R    AUBICLE 

•  '.AKY 
INK    VENA  CAVA 
IHOBACII    AORTA 


ANTERIOR  _CI  IMMUNICATING 
ANTERIOR 
CEREBRAL — 

MIDDLE  CEREBRAL  " 

OPHTHALMIC  . 

TEMPORAL . 

POST    COMMUNICATING 

POST   CEREBRAL - 

SUPERIOB  CEREBELLAR. 

SUP   STERN0-MAST0ID. 

BASILAR  - 
ANT.  INFERIOR 
CEREBELLAR  - 


L.  INT  CAROTID  . 
FACIAL  _ 


FIG.  81. 

'I'lio   art'Tiis    o!'    the    head    and    neck, 


THE    HEART    AND    VASCULAR    SYSTEM.  185 

Sphenomaxillary  portion : — 

Alveolar  or  posterior  dental  branch  (a.  aheolaris  superior  poste- 
rior), supplies  the  upper  molar  and  bicuspid  teeth,  antrum  and  gums; 
its  principal  branch  is  the  superior  dental; 

Infraorbital  (a.  infraorbitaUs) ,  passes  through  infraorbital  canal 
to  face: 

Posterior  or  descending  palatine  («.  palatina  descendens), 
descends  posterior  palatine  canal  and  runs  forward  to  foramen  of 
St<'iison; 

Vidian   (or.  canalis  pterygoidea) ,  accompanies  the  Vidian  nerve; 

Pterygopalatine,  supplies  Eustachian  tube  and  pharynx; 

Nasal,  or  sphenopalatine  (a.  sphenopalatine/,),  descends  through 
sphenopalatine  foramen  to  antrum,  sphenoidal  and  ethmoidal  cells. 

THE  INTERNAL  CAROTID  ARTERY  (A.  CAROTIS  INTERNA) 

arises  about  the  upper  border  of  the  thyroid  cartilage  from  the 
bifurcation  of  the  common  carotid.  It  ascends  in  front  of  the 
transverse  processes  of  the  cervical  vertebrae  to  the  carotid  fora- 
men in  the  petrous  portion  of  the  temporal  bone  to  supply  the 
anterior  part  of  the  brain,  the  eye  with  its  appendages,  and  send 
branches  to  the  nose  and  forehead.  It  gives  no  branches  until 
it  passes  through  the  carotid  canal,  where,  after  piercing  the 
dura  mater  at  the  anterior  clinoid  process,  it  divides  into  its 
terminal  branches — the  anterior  and  middle  cerebral. 

Relations. — The  internal  carotid  artery  in  the  neck  is  in  relation 
in  front  with  the  parotid  gland,  the  glossopharyngeal  nerve,  the  stylo- 
glossus and  stylopharyngeal  muscles,  and  is  covered  by  the  skin,  super- 
ficial and  deep  fascia';  behind  it  rests  upon  the  rectus  capitis  anticus 
major  and  has  resting  upon  it  the  superior  laryngeal  nerve  and  the 
sympathetic;  internally  it  is  in  relation  with  the  pharynx,  tonsil, 
superior  laryngeal  nerve  and  descending  pharyngeal  artery;  externally 
ii  is  in  relation  with  the  internal  jugular  vein  and  the  pneumogastric 
nerve. 

Its  branches  arc,  from  the  petrous  portion: — ■ 

Tympanic,  internal  or  deep  [ramus  caroticotympamcus) ,  sup- 
plies tympanum. 

From  the  cavernous  portion : — 

Artiriiv  rrr-< [ttaciili,  supply  the  Gasserian  ganglion  and  pituitary 
body; 

Anterior  meningeal  ('/.  menigea  anterior),  a  branch  from  the  pre- 
oeding  v—el  to  the  dura. 

Ophthalmic  ('/.  ophthalmica)  arises  about  tbe  position  of 
the  anterior  clinoid  process  and  passes  through  the  optic  fora- 
men to  the  outer  side  of  tin-  optic  ner\e  jo  reach  the  orbit.  At 
the   inner   angle   of   the   eye   it  divides   into    its  two   terminal 


186  HUMAN    ANATOMY. 

branches — the  frontal  and  the  nasal.     It  supplies  the  muscles 
and  the  globe  of  the  eye,  and  its  branches  may  be  divided  into 
two  groups — the  orbital  and  the  ocular. 
Orbital  group : — 

Lachrymal  (a.  laohrimaUs) ,  supplies  the  lachrymal  gland  and 
gives  off  a  malar  branch  which  passes  through  the  malar  bone  to  the 
temporal  fossa; 

Supraorbital  (a.  supraorbitals) ,  passes  out  through  the  supra- 
orbital foramen  to  supply  the  surrounding  structures; 

Posterior  ethmoidal  (a.  ethmoidalis  jjosterior) ,  descends  through 
the  posterior  ethmoidal  foramen  to  the  cells  and  adjacent  parts; 

Anterior  ethmoidal  (a.  ethmoidalis  anterior) }  through  the  ante- 
rior ethmoidal  foramen  to  the  nose; 

Internal  palpebral    (aa.  palpebrales  mediales) ,  supply  the  eyelids. 

Frontal  (a,,  frontalis),  supplies  the  skin  and  muscles  of  the  fore- 
head. 

Nasal  (a.  dorsalis  nasi),  supplies  the  lachrymal  sac  and  bridge  of 
the  nose. 

Ocular  group : — 

Muscular,  supply  the  muscles  of  the  eye; 

Anterior  ciliary  {aa.  ciliares  anteriores) ,  supply  the  iris,  piercing 
the  sclerotic  near  the  cornea ; 

Short  ciliary  (aa.  ciliaris  posteriores  breves),  supply  the  choroid 
and  ciliary  processes,  piercing  the  sclerotic  near  the  optic  nerve; 

Long  ciliary  (aa.  ciliares  posteriores  longw),  enter  with  the  short 
ciliary,  but  run  forward  to  the  iris; 

Arteria  centralis  retinae,  supplies  the  optic  nerve  and  the  retina. 

From  the  cerebral  portion : — 

Anterior  cerebral  (a.  cerebri  anterior),  supplies  the  ante- 
rior part  of  the  cerebrum,  the  optic  and  olfactory  nerves,  and  com- 
municates with  its  fellow  by  the  anterior  communicating; 

Middle  cerebral,  or  Sylvian  artery  ( a.  cerebri  media ) ,  ascends  in 
the  Sylvian  fissure,  and  supplies  the  middle  lobes  of  the  cerebrum; 

Posterior  communicating  (a.  communicans  posterior) ,  runs  back- 
ward to  join  the  posterior  cerebral; 

Anterior  choroid    (a.  choroidea) ,  supplies  the  choroid  plexus. 

THE    CIRCLE   OF    WILLIS    (CIRCULUS   ARTERIOSUS    [wiLLISl] ) 

is  an  anastomotic  circle  formed  at  the  base  of  the  brain  about 
the  pituitary  body,  between  the  branches  of  the  internal  carotid 
and  the  vertebral  arteries,  for  the  purpose  of  equalizing  the 
cerebral  circulation.  The  anterior  cerebrals,  from  the  internal 
carotids,  pass  forward  and  are  united  in  front  by  a  short  trunk, 
the  anterior  communicating.  The  posterior  communicating 
unites  the  internal  carotid  with  the  posterior  cerebral,  the  latter 
being  the  terminal  branches  of  the  basilar,  which  in  its  turn 
is  formed  by  the  union  of  the  two  vertebrals. 


Acromial  thoracic 


M   fl  KJ"H    I  HoRai  |c 


LONG  THORACIC 


HAUIAI.  ISDICIB 


nL^K  PALMAH  DIGITALS 


Fig.  82. 
The  arteries  of  thr»  upper  extremity. 


THE    HEART    AND    VASCULAR    SYSTEM.  18? 


TIIK     SUB<  LAVIAX     AKTERY    (A.     srBCLAVIA) 

on  the  right  side  arises  from  the  arteria  innominata,  hehind  the 
right  sternoclavicular  articulation,  and  on  the  left  side  directly 
from  the  arch  of  the  aorta.  They  pass  outward  to  the  outer 
margin  of  the  first  rib,  where  they  become  the  axillary,  being 
divided  in  their  course  by  the  scalenus  anticus  muscle  into  three 
portions — the  first  portion  to  the  inner  side  of  the  muscle,  sec- 
ond portion  behind  it,  and  the  third  portion  between  its  outer 
margin  and  the  lower  border  of  the  first  rib.  The  vessels  differ 
only  in  their  first  portions,  the  left  ascending  more  vertically. 

Relation The  first  portion  of  the  right  subclavian  is  in  relation 

in  front  to  the  internal  jugular  and  vertebral  veins,  the  sternohyoid  and 
sternothyroid  and  the  clavicular  portion  of  the  sternomastoid  muscles 
and  the*  pneumogastric,  phrenic,  and  cardiac  nerves;  behind  it  is  in 
relation  with  the  longus  colli  muscle,  the  transverse  process  of  the 
first  dorsal  or  seventh  cervical  vertebrae,  the  sympathetic  nerve,  and 
the  recurrent  laryngeal  nerve  beneath  with  the  pleura. 

The  first  portion  of  the  left  subclavian  artery  is  in  relation  in 
front  with  the  left  internal  jugular  and  innominate  veins,  the  left 
carotid  artery,  the  sternothyroid,  sternohyoid,  and  sternomastoid 
muscles,  the  "pleura  and  left  lung,  the  pneumogastric,  phrenic  and 
cardiac  nerves;  behind,  with  the  vertebral  column  and  longus  colli 
muscle,  the  esophagus,  thoracic  duct,  and  the  inferior  cervical 
ganglion  of  the  sympathetic;  on  the  inner  side  with  the  esophagus, 
thoracic  duct,  and  trachea,  and  on  the  outer  side  with  the  pleura.  The 
second  portion  of  the  subclavian  artery  on  either  side  is  in  relation  with 
the  subclavian  vein,  the  scalenus  anticus  muscle  and  the  phrenic 
nerve;  behind  with  the  middle  scalenus  muscle  and  pleura;  above  by 
brachial  plexus,  and  below  by  the  pleura.  The  third  portion  of  the 
subclavian  artery  on  either  side  is  in  relation  in  front  with  the  exter- 
nal jugular  vein  and  its  branches,  the  clavicle,  subclavius  muscle  and 
suprascapular  artery,  the  descending  branches  of  the  cervical  plexus 
and  the  cervical  fascia;  behind  with  the  scalenus  medius,  above  with 
the  omohyoid  muscle  and  the  brachial  plexus,  and  below  with  the  first 
rib. 

[te  branches  are: — 

1.  Vertebra]     i".    oertebraUs) .      5.  Transverse    cervical,    or 

2.  Thyroid  axis   [truncus  thy-  transversal  is    colli     (a. 

1 1 <>c<  i rifiilis) .  transversa  colli). 

:;.  Inferior  thyroid  (a.  thy-  0.  Internal  mammary  (a. 
/■<',»/<</   inferior).  mammaria  interna). 

4.  Suprascapular  [a.  trans-  7.  Superior  intercostal  [trim- 
versa  8cajnilrp).  cm  oostocervioalis). 

These  branches  are  all  given   off    from    the    first  portion. 
pi   the  Buperior  intercostal,  which  arises  on  the  right  side, 
from  the  second  portion. 


188  HUMAN    ANATOMY. 

1.  The  vertebral  artery  (a.  vertebralis)  passes  upward, 
enters  the  foramen  in  the  transverse  process  of  the  sixth  cervical 
vertebra,  and  ascends  through  the  foramina  until  it  reaches  the 
atlas,  when  it  runs  backward,  pierces  the  posterior  occipito- 
atloid  ligament  and  dura  mater  to  enter  the  skull  through  the 
foramen  magnum.  After  entering  the  cranium  it  passes  for- 
ward to  the  lower  border  of  the  pons  Varolii  where  it  unites 
with  its  fellow  of  the  opposite  side  to  form  the  basilar  artery. 
Its  branches  are — 

.    Cervical  branches  : — 

Lateral  spinal  (rami  spinales) ,  supply  the  spinal  cord  and  its 
membranes,  entering  the  spinal  canal  through  the  intervertebral 
foramina; 

Muscular,  supply  the  deep  muscles  of  the  neck. 

Cranial  branches: — 

Posterior  meningeal   (ramus  meningeus)   supply  the  falx  cerebelli ; 

Anterior  spinal  (a.  spinalis  anterior),  supplies  the  cord;  uniting 
with  branches  from  the  inferior  thyroid,  intercostals,  and  lateral  sacral, 
descend  to  the  cauda  equina; 

Posterior  spinal  (a.  spinalis  posterior),  descends  in  the  same 
manner  as  the  anterior; 

Posterior  inferior  cerebellar  (a.  cerebelli  inferior  posterior) ,  sup- 
plies the  inferior  surface  of  the  cerebellum  and  the  choroid  plexus  of 
the  fourth  ventricle. 

The  branches  of  the  basilar  artery  (a.  hasilaris)  are: — 

Transverse  (rami  ad  pontem),  to  the  pons  Varolii  and  inferior 
surface  of  the  cerebellum; 

Anterior  inferior  cerebellar  (a.  cerebelli  inferior  anterior),  a 
branch  of  the  transverse; 

Superior  cerebellar  (a.  cerebelli  superior),  supplies  pia  mater, 
pineal  gland  and  velum  interpositum. 

Posterior  cerebral  (a.  cerebri  posterior'),  to  posterior  lobes  of 
cerebrum  and  choroid  plexus. 

2.  The  thyroid  axis  {truncus  tliyreocervicalis)  consists  of 
three  branches — the  inferior  thyroid,  the  suprascapular  and  the 
transversalis  colli. 

3.  The  inferior  thyroid  artery  (a.  thyreoid 'ea  inferior)  is 
distributed  to  the  thyroid  gland,  its  branches  being: — 

Inferior  laryngeal  (a.  laryngea  inferior),  to  muscles  and  mucous 
membrane  of  larynx; 

Tracheal  (rami  tracheales) ,  to  the  trachea,  anastomosing  with  the 
bronchial  arteries; 

Esophageal    (rami  cesophagei) ,  to  esophagus; 

Ascending  cervical  ( a,  cervicalis  ascendens ) ,  supplies  the  spinal 
cord  and  membranes,  vertebrae,  and  muscles  of  neighborhood; 

Muscular  (rami  muscular e s) ,  to  inferior  constrictor  of  pharynx, 
scalenus  anticus,  and  other  muscles. 


THE    HEART    AND    VASCULAR    SYSTEM.  189 

-i.  The  suprascapular  artery — transversal  is  humeri  (a. 
transversa  scapula)  passes  beneath  the  posterior  belly  of  the 
omohyoid  to  the  upper  border  of  the  scapula,  passing  over  the 
transverse  ligament  of  the  scapula  to  the  supraspinous  fossa, 
where  it  is  distributed  to  the  supraspinatus,  sternomastoid,  and 
other  muscles,  and  by  means  of  the  supra-acromial  branch  to 
the  skin  over  the  acromion,  anastomosing  with  the  posterior 
circumflex  and  acromial  thoracic  arteries. 

In  about  50  per  cent,  of  bodies  tbis  artery  will  be  found  to  arise 
from  tbe  third  portion  of  tbe  subclavian. 

5.  The  transversalis  colli  (a.  transversa  colli)  passes  out- 
ward to  the  trapezius  muscle,  where  it  divides  into 

The  (a)  superficial  cervical  (ramus  ascendens),  an  important 
branch  passing  beneath  the  trapezius  to  anastomose  with  the  superficial 
branch  of  the  arteria   princeps  cervieis; 

And  the  (b)  superficial  posterior  scapular  (ramus  descendens), 
the  larger  passing  to  and  along  the  upper  and  posterior  border  of  the 
scapula,  beneath  the  levator  anguli  scapulae,  rhomboidei,  latissimus 
dorsi  and  trapezius,  to  anastomose  with  the  subscapular,  suprascapular, 
and  posterior  branches  of  the  interoostals. 

G.  The  internal  mammary  (a.  mammar'm  interna)  arises 
from  the  subclavian,  opposite  the  thyroid  axis,  and  descends 
upon  the  internal  surfaces  of  the  costal  cartilages  to  a  point 
in  the  sixth  intercostal  space,  where  it  divides  into  the  musculo- 
phrenic and  the  superior  epigastric.     Its  branches  are: — 

Tomes  nervi  phrenici — superior  phrenic  (a.  pericardiacophrenica) , 
supplies  diaphragm,  passing  between  the  pleura  and   pericardium; 

Mediastinal  (aa.  mediastinalrs  ante) iores) ,  to  the  anterior 
mediastinum ; 

Pericardiac,  to  upper  portion  of  pericardium; 

Sternal    (rami  8ti  males) ,  to  posterior  surface  of  sternum; 

Anterior  intercostal  (rami  inter  cost  ales) ,  to  fifth  or  sixth  upper 
intercostal   spaces; 

Perforating  (rami  perforantes) ,  perforate  the  intercostal  spaces 
to  Bupply  the  mammary  gland; 

Musculophrenic  (a.  musculophrenica) ,  supplies  lower  part  of  peri- 
cardium, diaphragm,  and  upper  part  of  abdominal  muscles; 

Superior  epigastric  (a.  epigastrica  superior),  supplies  the  rectus 
muscle,  and  anastomoses  with  the  deep  epigastric  from  the  external 
iliac. 

7.  The  superior  intercostal  artery  (truncus  costocervicalis) 

arises   from  the  subclavian,  behind  the  anterior  scalenus  muscle, 

and  descends  behind  the  pleura  and  anastomoses  with  the  firsi 
aortic  intercostal  artery.     It  gives  off  branches  in  the  intercostal 


190  HUMAN   ANATOMY. 

spaces  to  the  spinal  cord  and  its  membranes  and  the  posterior 
spinal  muscles.  Its  principal  branch  is  the  deep  cervical  (pro- 
funda cervicis). 

THE    AXILLARY    ARTERY     (A.    AXILLARIS) 

is  the  continuation  of  the  subclavian,  extending  outward  from 
the  lower  edge  of  the  first  rib  to  the  lower  margin  of  latissimus 
dorsi  and  teres  major  muscles,  where  it  becomes  the  brachial. 
It  is  divided  by  the  pectoralis  minor  into  three  parts — the  first 
portion  above,  the  second  portion  behind,  and  the  third  portion 
below  that  muscle.  It  passes  through  the  space  known  as  the 
axilla  (vide  Regions). 

Relations. — First  portion:  The  first  portion  of  the  axillary  is  in 
relation  in  front  with  the  subclavius  and  pectoralis  major  muscles, 
costocoracoid  membrane,  acromial  thoracic  and  cephalic  veins  and  the 
external  anterior  thoracic  nerve;  the  axillary  vein  to  its  inner  side, 
the  brachial  plexus  to  its  outer  side,  and  the  posterior  thoracic  nerve 
and  serratus  magnus  behind.  Second  portion:  The  relations  of  the 
second  portion  are  niuch  the  same  as  the  first,  with  the  addition  of  the 
pectoralis  minor  in  front  and  the  division  of  the  brachial  plexus  sur- 
rounding the  vessels.  Third  portion:  The  third  portion  is  in  relation  in 
front  with  the  inner  head  of  the  median  nerve  and  the  pectoralis  major 
muscle;  to  the  inner  side  with  the  axillary  vein,  internal  cutaneous  and 
ulnar  nerves;  to  the  outer  side,  the  median  and  musculocutaneous 
nerves  and  coraeobrachialis  muscle;  and,  behind,  the  circumflex  and 
musculospiral  nerves  and  the  subscapulars,  latissimus  dorsi  and  teres 
major  muscles. 

Its  branches  are: — 

Superior  thoracic  (a.  thoracalis  supremo),  supplies  the 
pectoralis  major  and  minor  muscles; 

Acromial  thoracic  (a.  thoracoacromialis) ,  gives  off  three 
branches — acromial,  thoracic  and  descending,  supplying  the 
pectoralis  major  and  minor,  serratus  and  deltoid; 

Long  thoracic  (a.  thoracalis  lateralis),  follows  the  lower 
border  of  the  pectoralis  minor  to  supply  the  serratus,  pectoralis 
major  and  minor,  and  mammary  glands; 

Alar  thoracic  supplies  the  axillary  glands; 

Subscapular  (a.  subscapulars),  arises  from  the  axillary 
artery  about  the  level  of  the  lower  border  of  the  subscapularis 
muscle.  It  passes  backward  and  downward  to  the  inferior  dor- 
sum of  the  scapula.  Its  branches  anastomose  with  the  posterior 
scapular  and  the  suprascapular.    They  are : — 

Subscapular  (a.  subscapularis) ,  supplies  the  subscapularis  muscle; 

Dorsalis  scapulae  (a.  circurnflexa  scapula'),  is  distributed  to  the 
infraspinous  fossa,  anastomosing  with  the  posterior  scapular  and  supra- 
scapular arteries; 


THE    HEART   AND    VASCULAR    SYSTEM.  191 

Median  branch,  descends  the  axillary  border  of  the  scapula  to 
supply  teres  muscles. 

Posterior  circumflex  (a.  circumfiexa>  humeri  posterior),  en- 
circles the  neck  of  the  humerus  to  supply  the  shoulder  joint  and 
the  deltoid  muscle; 

Anterior  circumflex  (a.  circumfiexa  humeri  anterior),  de- 
scends beneath  the  short  head  of  biceps  and  coracobrachial 
muscles  to  supply  the  shoulder  joint. 

THE    BRACHIAL    ARTERY    (A.    BRACHIALIS) 

commences  at  the  lower  border  of  the  latissimus  dorsi  and  teres 
major  muscles  and  descends  on  the  front  and  inner  aspect  of 
the  arm  to  half  an  inch  below  the  middle  of  a  line  drawn 
through  the  condyles  of  the  humerus,  where  it  terminates  by 
dividing  into  the  radial  and  ulnar  artery. 

Relations. — It  is  covered  in  front  by  the  skin,  superficial  and  deep 
fascia,  and  is  crossed  by  the  median  nerve;  behind  it  rests  upon  the 
triceps,    brachialis    anticus    and    coracobrachial    muscles; 

And  is  in  relation  with  the  musculospiral  nerve  and  the  superior 
profunda  artery ;  to  the  outer  side  above  it  is  in  relation  with  the 
biceps  and  coracobrachialis  muscles  and  the  median  nerve;  and  on 
the  inner  side  with  the  internal  cutaneous  and  ulnar  nerve,  and  the 
basilic  vein  and  median  nerve  below. 

At  the  bend  of  the  elbow  it  is  crossed  by  the  bicipital  fascia. 
Its  branches  are: — 

-Superior  profunda  (a.  profunda  brachii),  accompanies  the 
musculospiral  nerve  to  supply  the  triceps,  deltoid  and  coraco- 
brachialis muscles; 

Nutrient  artery  (a.  nutricia  humeri),  supplies  the  shaft  of 
the  humerus; 

Inferior  profunda  {a.  eollateralis  ulnaris  superior),  accom- 
panies the  ulnar  nerve  to  supply  the  triceps  muscle  and  struc- 
tures about  the  internal  condyle ; 

Anastomotica  magna  (a.  eollateralis  ulnaris  inferior), 
forme  as  anastomosis  on  the  lower  posterior  aspect  of  the  arm, 
with  branches  from  the  inferior  profunda  and  recurrent  ulnar 
-'.•Is.     It  supplies  the  triceps; 

Muscular  (rami  iinisiiilares),  supply  the  muscles  on  the 
anterior  aspect  of  the  arm. 

THE    BADIAL    ARTERY    (A.    RADIALIS) 

:ds  from  the  bifurcation  of  the  brachial  below  the  bend 
of  the  elbow  to  the   wrist,   where   it  winds  around  the  carpus 


192  HUMAN    ANATOMY. 

beneath  the  extensor  tendons  of  the  thumb,  passes  between  the 
two  heads  of  the  first  dorsal  interosseous  muscle  and  into  the 
palm  of  the  hand,  where  it  forms  the  deep  palmar  arch,  anasto- 
mosing with  the  deep  branch  of  the  ulnar  artery.  Its  branches 
are,  in  the  forearm : — 

Radial  recurrent  (a.  recurrens  radialis) ,  supplies  the  braehialis 
anticus  and  supinator  longus  and  brevis; 

Muscular  {rami  musculares) ,  supply  the  radial  muscles; 

Superficialis  volse  (ramus  volaris  superficialis) ,  supplies  the 
muscles  of  the  thumb  and  anastomoses  with  the  ulnar  to  form  the 
superficial  palmar  arch; 

Anterior  radial  carpal  (ramus  carpeus  volaris),  supplies  the 
wrist-joint. 

In  the  wrist: — 

Posterior  radial  carpal  (ramus  carpeus  dorsalis) ,  supplies  the 
wrist-joint,  forms  the  posterior  carpal  arch,  and  gives  off  the  dorsal 
interosseous  arteries; 

Metacarpal,  is  called  the  first  dorsal  interosseous;  it  supplies  the 
index  and  middle  finger; 

Dorsales  pollicis,  supply  the  back  of  the  thumb; 

Dorsalis  indicis,  supplies  the  outer  and  dorsal  side  of  the  index 
finger. 

In  the  hand: — 

Princeps  pollicis  (a.  princeps  pollicis),  supplies  the  sides  of  the 
palmar  aspect  of  the  thumb; 

Radialis  indicis  (a.  volaris  indicis  radialis),  supplies  the  radial 
side  of  index  finger; 

Perforating  (rami  perf  or  antes) ,  anastomose  with  dorsal  interos- 
seous arteries; 

Interosseous  (aa.  metacarpew  volares) ,  anastomose  with  digital 
branches  of  superficial  palmar  arch. 

THE    ULNAR    ARTERY   (A.    ULNARIS) 

descends  from  the  bifurcation  of  the  brachial  below  the  bend 
of  the  elbow  to  the  ulnar  border  of  the  wrist,  passing  beneath 
all  the  superficial  flexors  excepting  the  flexor  carpi  ulnaris, 
crosses  over  the  annular  ligament  at  the  radial  side  of  pisiform 
bone,  and  enters  the  palm  to  form  the  superficial  palmar  arch, 
anastomosing  with  the  superficialis  volse  from  the  radial.  Its 
branches  are,  in  the  forearm : — 

Anterior  ulnar  recurrent  (a.  recurrentes  ulnaris  anterior),  sup- 
plies the  pronator  radii  teres  and  braehialis  anticus  muscles; 

Posterior  ulnar  recurrent  (a.  recurrentes  ulnaris  posterior),  sup- 
plies the  joint  and  neighboring  muscles,  and  anastomoses  freely; 

Interosseous  (a.  interossea  communis),  passes  backward  to  the 
upper  border  of  the  interosseous  membrane,  where  it  divides  into 


THE    HEART    AND    VASCULAR    SYSTEM. 


193 


Anterior  branch  (a.  mterossea  volaris),  descends  on  the  front  of 
the  interosseous  membrane; 

Posterior  (a.  intcrossea  dorsalis) ,  descends  on  the  posterior  as- 
pect of  the  foramen  and  gives  off  a  recurrent  interosseous  branch- 

Muscular  {rami  musculares),  to  muscles  on  ulnar  side  of  forearm. 

In  the  wrist: — 

Anterior  carpal  (ramus  carpeus  volaris),  supplies  the  front  of 
wrist  and  anastomoses  with  the  carpal  branches  of  radial  artery- 

Posterior  carpal  (ramus  carpeus  dorsalis),  passes  beneath  the  ten- 
don ot  flexor  carpi  ulnaris  and  forms  posterior  carpal  branch. 

In  the  hand  : — 

Deep,  or  communicating  branch  (ramus  volaris  profundus)  passes 
between  the  flexor  and  abductor  minimi  digiti  to  form  part  of  deen 
palmar  arch;  *  x 

«i  l«    Dlgfi1tal',.!"Pply-  the  Ul!\a,r  Skle  of  the   little   finSer  and  adjoining 
sides  of  the  little,  ring,  middle  and  index  Angers. 

THE    DESCENDING    AORTA. 

The  thoracic  aorta  (aorta  thoracalis)  extends  from  the 
.wer  border  of  the  fifth  dorsal  vertebra  on  the  left  side  to  about 
the  last  dorsal  vertebra,  where  by  passing  through  the  aortic 
opening  m  the  diaphragm  it  becomes  the  abdominal  aorta. 

Relations— It  is  in  relation  in  front  with  the  left  bronchus  esoph- 
agus pericardium  and  left  pulmonary  artery;  behind  it  rests  uj'xuxe 
vertebral  column  and  is  ,n  relation  with  the  vena  azygos  minor;  on  the 
right  side  it  is  m  relation  with  the  thoracic  duct;  the  esophLms  at 
its  upper  part  and  the  vena  azygos  major;  on  the  left  side  with  'the 
left  lung,  the  pleura,  and  the  esophagus  below. 

The  branches  of  the  thoracic  aorta  are : 

Pericardiac  (rami  pericardiaci) ,  supply  the  pericardium- 
Bronchial  (aa.  bronchioles),  two  or  three  in  number,  sup- 
ply the  bronchi ;  '      l 
Esophageal  (aa.  a>  so  phage®),  supply  the  esophagus  • 
Posterior    mediastinal    (rami    mediastinales) ,    supply    the 
neighboring  pleura  and  lymphatic  glands; 

Intercostal  (aa.  intercostal es),  ten  on  each  side,  supply  the 
intercostal  spaces.  They  divide  into— anterior  branch,  to  inter- 
costal and  pectoral  muscles;  posterior  branch,  to  spinal  column 
and  dorsal  muscles. 

THE  ABDOMINAL  AORTA  (AORTA  ABDOMINALIS) 

descends  from  the  Inst  dorsa]  vertebra  at  the  aortic  opening  of 
the  diaphragm,  to  opposite  the  fourth  lumbar  vertebra,  a  little 


194  HUMAN   ANATOMY. 

to  the  left  of  the  median  line,  where  it  divides  into  the  two 
common  iliac  arteries. 

Relations. — Th"  abdominal  aorta  is  in  relation  in  front  with  the 
pancreas,  transverse  duodenum,  stomach,  and  lesser  omentum,  the  mes- 
entery, splenic  vein,  left  renal  vein,  celiac,  solar  and  aortic  plexuses; 
behind,  it  is  in  relation  with  the  vertebral  column,  the  thoracic  duct, 
the  left  lumbar  veins  and  the  receptaculum  chyli;  on  the  right  side 
with  the  inferior  vena  cava,  vena  azygos,  thoracic  duct,  the  right  crus 
of  the  diaphragm  above,  and  the  right  semilunar  ganglion;  on  the  left 
side  with  the  left  semilunar  ganglion  and  the  sympathetic  nerve. 

The  branches  of  the  abdominal  aorta  are : — 
Phrenic,  two  in  number,  supply  the  diaphragm; 
Celiac  axis  (a.  ccdiaca),  divides  into  three  large  branches, 
the  gastric,  hepatic  and  splenic; 

1.  Gastric,  or  coronaria  ventriculi  (a.  gastrica  sinistra),  is 
the  smallest,  and  supplies  the  lesser  curvature  of  the  stomach ; 

2.  Hepatic  (a.  hepatica),  enters  the  transverse  fissure  of 
the  liver,  and  divides  into  two  branches  to  supply  the  lobes  of 
the  liver.    It  gives  off : — 

Pyloric    (a.  gastrica  dextra),  to  lesser  curvature  of  stomach; 

Gastroduodenalis,  which  descends  behind  the  pylorus,  and  divides 
into 

Pancreaticoduodenalis  superior  branch  to  supply  the  pancreas  and 
duodenum ; 

Gastroepiploica  dextra,  along  the  greater  curvature  of  the 
stomach  from  right  to  left. 

Cystic   ( a.  cystica ) ,  supplies  the  gall-bladder. 

3.  Splenic  (a.  lienalis),  the  largest  of  the  three,  supplies 
the  spleen  and  gives  off  the 

(a)  Pancreatic   (rami  pancreatici) — to  the  pancreas; 

(b)  Gastroepiploica  sinistra,  runs  from  left  to  right,  along  the 
greater  curvature,  to  join  the  gastroepiploica  dextra; 

(c)  Gastric — vasa  brevia  (aa.  gmtricw  brevis),  supply  the  fun- 
dus of  the  stomach. 

Superior  mesenteric  (a.  mesenterica  superior),  supplies  the 
small  intestine  (except  first  part  of  the  duodenum)  and  the 
large  intestine  as  far  as  the  splenic  flexure,  and  part  of  the 
descending  colon.    It  gives  off: — 

(a)  Inferior  pancreaticoduodenal  (a.  pancreaticoduodenalis  infe- 
rior), supplies  duodenum  and  pancreas; 

(b)  Vasa  intestini  tenuis  (aa.  intestinales) ,  supply  nearly  the 
whole  length  of  the  small  intestine  (ileum  and  jejunum)  ; 

(c)  Ileocolic  (a.  ileocolica) ,  descends  to  the  right  iliac  fossa,  be- 
tween the  layers  of  the  mesentery,  and  divides  into  two  branches; 

(d)  Right  colic  artery  (colica  dextra),  passes  to  the  middle  of  the 
ascending  colon,  to  divide  into  two  branches; 


THE    HEART    AND    VASCULAR    SYSTEM. 


195 


(«)  Middle  colic  artery  (colica  media),  ascends  in  the  layers  of 
the  transverse  mesocolon,  to  divide  into  two  branches. 

Suprarenal  (a.  suparenalis  media),  supply  the  suprarenal 
bodies ; 

Renal  (aa.  renales),  supply  the  kidneys,  a  large  trunk  on 
each  side  springing  directly  from  the  aorta; 

Spermatic  (aa.  spermatica}  interna'),  descend  to  supply  the 
testicles,  and  in  their  passage  form  one  of  the  constituents  of 
the  spermatic  cord; 


Fig.  83. 

Abdominal  aorta:  1,  phrenic;  2,  celiac  axis;  3,  superior  mesen- 
t«  ri<- ;  4,  suprarenal:  5,  renal;  G,  spermatic;  7,  inferior  mesenteric; 
8,   lumbar;   9,   sacra  media. 

Inferior  mesenteric  (aa.  mesenterica  inferior),  gives  off: — 

(a)    l.cfi  colic  [coUca  amisira),  supplies  the  descending  colon; 
3igmoid   (aa.  aigmoidece),  supplies  the  sigmoid  flexure  of  the 
colon ; 

(c)  Superior  hemorrhoidal  (».  h<r»i<>rrh<>i<l(ilis  superior) ,  the  con- 
tinuation of  tin-  inferior  mesenteric,  supplies  the  mucous  and  muscular 
coate  "i  the  rectum  <>n  it-  posterior  aspect. 

Lumbal  branches  («".  Iwmbales),  four  or  five  on  each  side. 
tackward  and  outward  and  divide  into  the 


196  HUMAN    ANATOMY. 

Dorsal  branches  (rami  dorsales),  supply  the  spinal  cord, 
muscles,  and  skin  of  back ; 

Spinal  branches  (rami  spinales),  divide  within  the  spinal 
canal,  ascend  and  descend,  and  form  an  arterial  network 
throughout  the  whole  length  of  the  spinal  canal; 

Abdominal  branches  (rami  parietales),  supply  the  abdom- 
inal walls; 

Middle  sacral  (a.  sacralis  media),  is  the  continuation  of 
the  abdominal  aorta,  descending  in  the  middle  of  the  sacrum 
to  the  upper  part  of  the  coccyx. 

THE    COMMON    ILIAC    ARTERIES    (AA.    ILIAC.E    COMMUNES) 

descend  from  the  bifurcation  of  the  abdominal  aorta,  opposite 
the  body  of  the  fourth  lumbar  vertebra,  to  a  point  midway 
between  the  last  lumbar  vertebra  and  the  sacrum,  where  they 
divide  into  the  external  and  internal  iliac  arteries.  The  right 
common  iliac  is  a  little  larger  than  the  left,  and  passes  more 
obliquely  outward. 

Relations. — The  right  common  iliac  is  in  relation  in  front  with  the 
small  intestine,  the  ureter,  the  peritoneum  and  the  sympathetic  nerves; 
behind,  with  the  left  and  right  common  iliac  veins,  and  to  its  outer 
side  it  rests  upon  the  psoas  musole,  and  is  in  relation  with  the  vena 
cava  and  the  right  common  iliac  vein.  The  left  common  iliac  is  in 
relation  in  front  with  the  ureter,  the  peritoneum,  the  superior  hemor- 
rhoidal artery  and  the  sympathetic  nerves;  behind,  with  the  left  com- 
mon iliac  vein,  to  its  outer  side  the  psoas  muscle,  and  to  its  inner  side 
the  left  common  iliac  vein. 

The  common  iliac  arteries  give  off  a  few  unimportant 
branches  to  the  ureters,  peritoneum,  etc. 

the  internal  iliac  or  hypogastric  artery 
(a.  hypogastrica) 

is  about  an  inch  and  a  half  in  length,  extending  from  the  bifur- 
cation of  the  common  iliac,  about  the  sacrolumbar  junction,  to 
the  upper  border  of  the  great  sacrosciatic  foramen,  where  it 
divides  into  the  anterior  and  posterior  trunks. 

The  branches  from  the  anterior  trunk  are: — 
Superior   vesical    (a.    vesiculis   superior),    is   the   pervious 
remains  of  the  fetal  hypogastric  artery.     It  supplies  the  apex 
and  body  of  bladder,  ureter  and  vas  deferens; 

Middle  vesical  (a.  vesiculis  medialis),  supplies  the  base  of 
the  bladder  and  part  of  vesiculae  seminales ;  it  may  be  given  off 
from  the  superior  vesical; 


r  jit.  suprarenal 
cystic 


R.  MID   SUPRARENAL. 
INK.  PAXCREATICO  DUODE.XAI 
GASTRO-DUODEN  U. 
R.  INF.  SUPRARENAL 
SUP   PAXCREATICO  DUODENAL. 
R.  GASTROEPIPLOIC 
R.  RENAL 
MIDDLE  COLIC 
RIGHT  COLIC 
LUMBAR 
SPERMATIC 
ABDOMINAL   AORTA 
INF.  MESENTERIC 
MIDDLE  SACRAL 
R.  COMMON  ILIAC 
SUP    HEMORRHOIDAL 
ILIO  LUMBAR 
R    INT    ILIAC 
R.  EXT.  ILIAC 
POST.  TRUNK  OF  INT    ILIAC 
ANT  TRUNK  OF  INT.  ILIAC. 
SUPERIOR  VF-I.  n 
OBLITERATED  I)  I 
OBTURATOR 
INFERIOR  VESICAL 
MIDDLE  VESICAL 
MID   BiCMOKRHOTDAJ 

INTERNAL   II  HI 
SCIATIC 


MIDDLE  VESICAL 


DEEP  EriUASTRIC 


Fig.  84. 

The  arteries  of  the  trunk. 


THE    HEART   AND    VASCULAR    SYSTEM.  197 

Inferior  vesical  (a.  vesicalis  inferior),  supplies  the  prostate 
gland,  base  of  bladder  and  vesiculae  seminales ; 

Middle  hemorrhoidal  (a.  hcemorrhoiddlis  media),  supplies 
part  of  the  rectum  ; 

Obturator  (a.  obiuratoria),  passes  along  the  side  of  the 
pelvis  to  the  obturator  foramen,  through  which  it  passes.  It 
gives  off  within  the  pelvis  the  iliac  (ramus  ifiacus),  vesical 
1  ram  us  vesicalis),  and  pubic  (ramus  pttbicus)  branch; 

Internal  pudic  (a.  pudenda  interna),  supplies  the  external 
organs  of  generation.  It  passes  out  of  the  pelvis  through  the 
great  sacrosciatic  foramen,  winds  around  the  ischial  spine,  and 
re-enters  the  pelvis  through  the  lesser  sacrosciatic  foramen. 

It  gives  off  the  following  branches  in  the  perineum : — 

(a)  Inferior  hemorrhoidal  (a.  hcBmorrhoidalis  inferior),  supplies 
the  muscles  and  skin  of  the  anus; 

(b)  Superficial  perineal  (a.  perinei) ,  supplies  the  erector  penis 
and  accelerator  urinae  muscles  and  the  scrotum; 

(c)  Transverse  perineal,  crosses  the  perineum  on  the  transversus 
muscle,  which,  together  with  the  structures  between  the  bulb  and  anus, 
it  supplies; 

(d)  Bulbourethral,  artery  of  the  bulb  (a.  bulbi  urethras),  sup- 
plies the  bulb  of  the  spongy  body  and  Cowper's  gland; 

(e)  Cavernous  [a.  profunda  penis),  supplies  the  corpus  caver- 
nosum,  and  is  one  of  the  terminal  branches: 

{f)  Dorsal  artery  of  penis,  or  clitoris  (a.  dorsalis  penis),  runs 
forward  on  the  dorsum  and  supplies  the  glans  and  prepuce. 

In  the  female  the  internal  pudic  artery  is  of  smaller  size, 
but  its  course  and  distribution  is  quite  analogous  to  its  study 
in  the  male  subject,  i.e.,  the  superficial  perineal  artery  supplies 
the  labia  pudendi ;  the  artery  of  the  bulb,  the  vestibule,  and  the 
vaginal  erectile  tissue,  the  artery  of  the  corpus  cavernosum,  the 
clitoris;  the  arteria  dorsalis  clitoridis,  the  dorsal  surface  of  the 
clitoris,  being  distributed  to  the  membranous  fold  in  the  glans 
clitoris,  the  analogue  of  the  male  prepuce. 

Sciatic  artery  supplies  the  muscles  at  the  back  of  the  pelvis, 
coccygeug,  pyriformifl  and  levator  ani,  and  passes  out  of  the 
greal  sacrosciatic  foramen  to  follow  the  course  of  the  sciatic 
Its  branches  external  to  the  pelvis  are: — 

Coccygeal,  supplies  back  part  of  coccyx; 

Inferior  gluteal  [a.  gluteal  inferior),  to  the  gluteus  maximus 
muscle : 

<  omes  nervi  iachiadici  ('/.  lomilaiis  ».  ixchiadici),  runs  in  the 
rabctance  of  the  great  sciatic  nerve; 

Mii-enlar,   to  the  back    part  of   the   hip; 
Articular,   to  supply  the  capsule  of  the  hip-joint. 


198  HUMAN    ANATOMY. 

Uterine  (a.  uterina),  is  distributed  to  body  of  uterus,,  giv- 
ing branches  to  the  ureter  and  bladder ; 

Vaginal  (a.  vaginalis),  supplies  the  mucous  membrane  of 
the  vagina,  giving  branches  to  the  rectum  and  neck  of  the  blad- 
der.   It  is  analogous  to  the  inferior  vesical,  in  the  male. 

From  the  posterior  trunk 

Iliolumbar  (a.  iliolumbalis)  gives  off  two  branches: — 

Lumbar  {ramus  lumbalis),  supplies  quadratus  lumborum 
and  psoas  muscles; 

Iliac  {ramus  iliacus),  supplies  iliacus,  gluteal  and  abdomi- 
nal muscles. 

Lateral  sacral  {a.  sacralis  lateralis),  are  two  in  number — 
the  superior  and  inferior,  supplying  the  contents  of  the  sacral 
canal ; 

Gluteal  {a.  glutece  superior),  gives  a  superficial  and  deep 
branch  to  supply  the  gluteus  maximus,  medius  and  minimus 
muscles. 

THE  EXTERNAL  ILIAC  ARTERY    (A.    ILIACA  EXTERNA) 

extends  from  the  bifurcation  of  the  common  iliac  to  Poupart's 
ligament,  under  which  it  passes  to  become  the  femoral. 

Relations. — It  is  in  relation  in  front  with  the  peritoneum  and 
intestines,  circumflex  iliac  vein,  spermatic  vessels,  genitocrural  nerve 
and  the  lymphatic  vessels  and  nerves;  behind,  it  rests  upon  the  psoas 
muscle,  and  is  in  relation  with  the  external  iliac  vein,  which,  together 
with  the  vas  deferens,  is  also  in  relation  to  it,  on  its  inner  side,  beneath 
Poupart's  ligament.  On  its  outer  side  it  is  in  relation  with  the  psoas 
inagnus  and  iliac  fascia. 

Its  branches  are : — 

The  deep  epigastric  {a.  epigastrica  inferior),  arises  above 
Poupart's  ligament  and  ascends  obliquely  inward  between  the 
transversalis  fascia  and  peritoneum  to  the  rectus  muscle,  in 
which  it  ascends  to  anastomose  with  the  termination  of  the 
internal  mammary  artery.     It  gives  off: — 

Cremasteric  {a.  spermatica  externa  [male];  a.  ligamenti  teretis 
uteri  [female] )  branch,  to  supply  the  cremasteric  muscle; 

Pubic  ( ramus  pubicus ) ,  crossing  Poupart's  ligament  to  descend 
to  the  inner  side  of  the  femoral  ring,  and 

.     Muscular,  to  supply  abdominal  muscles  and  the  peritoneum. 

The  deep  circumflex  iliac  {a.  circamflexa  ilium  profunda) 
ascends  outwardly  behind  Poupart's  ligament  to  the  crest  of  the 
ilium,  where  it  gives  off : — 

Muscular  branches,  to  supply  the  abdominal  muscles. 


ILIOLl  MPAR 


1MTEKNAI    Hue 


01  m  i    mi  bi  'i  roi 


]'•[<:.  86. 
The  arteries  of  the  lower  extremity. 


THE    HEART   AND    VASCULAR    SYSTEM.  199 

THE    FEMORAL    ARTERY    (A.    FEMORALIs) 

extends-  from  Pouparfs  ligament  down  the  inner  side  of  the 
thigh  to  the  opening  in  the  adductor  magnus — Hunter's  canal 
■  lis  adductorius  |  llunteri]),  where  it  becomes  the  popliteal. 
Its  course  corresponds  to  a  line  drawn  from  a  point  midway 
between  the  anterior  superior  spine  of  the  ilium  and  the  sym- 
physis pubis  to  the  inner  tuberosity  of  the  internal  condyle.  In 
the  upper  part  of  its  course  it  is  superficial,  where  it  passes 
through  Scarpa's  triangle  (trigonum  femorale),  but  in  the  lower 
part  it  passes  backward  and  becomes  very  deep.  Where  it  passes 
under  Pouparfs  ligament  the  femoral  vein  is  to  the  inner  side, 
and  the  anterior  crural  nerve  to  the  outer  side;  thus,  from 
within  outward,  Y.  A.  N. 

Relations. — It  is  in  relation  in  front  with,  the  sartorius,  the  long 
saphenous  nerve,  a  branch  of  the  anterior  crural  nerve,  and  is  covered 
liv  the  fascia  lata;  behind,  it  is  in  relation  with  the  psoas  magnus, 
adductor  longus,  adductor  magnus  and  pectineus  and  the  profunda 
vein,  and  about  the  middle  with  the  femoral  vein;  at  its  inner  side  it 
is  in  relation  with  the  sartorius  and  adductor  longus  muscles,  and  at 
its  upper  part  with  femoral  vein;  on  the  outer  side,  with  the  vastus 
internus,  and  at  its  lower  part,  the  femoral  vein. 

The  branches  of  the  femoral  artery  are: — 

Superficial  epigastric  (a.  epigastrica  superficialis) ,  descends 
through  the  saphenous  opening  in  the  fascia  lata,  and  ascends 
in  abdomen,  supplying  the  skin,  inguinal  glands  and  superficial 
fascia; 

Superficial  circumflex  iliac  (a.  circumflexa  ilium  superfi- 
cialis),  passes  outward  to  the  skin  of  the  groin  and  over  crest 
of  ilium  ; 

Superficial  external  pudic  (a.  pudenda  externa  superfi- 
cialis),  supplies  the  skin  on  the  lower  part  of  the  abdomen; 

Deep  external  pudic  (a.  pudenda  externa  profunda),  sup- 
plies the  scrotum  in  the  male,  the  labia  pudendi  in  the  female; 

Profunda  femoris,  arises  about  two  inches  below  Pouparfs 
Hi,  and  passes  beneath  the  adductor  longus,  giving  off 
the  following: — 

External  circumflex  («.  circumflexa  femoris  lateralis),  gives 
off  ascending,  transverse  and  descending  branches,  supplying  the 
muscles  on  the  front  of  the  thigh  as  low  as  the  knee; 

Internal  circumflex  (a.  circumflexa  femoris  medialis), 
internally,  supplying  the  adductor  muscles  and  the  hip 
joint; 

Thn-c  perforating  (ua.  perforans  prima,  secunda,  tertia), 
the  adductor  magnus  and  brevis,  and  supply  the  flexor 


200  HUMAN    ANATOMY. 

muscles  of  the  thigh,  and  give  off  the  medullary  nutrient  artery 
(a.  nutricia  femoris).  The-  vessel  terminates  by  a  fourth  per- 
forating. 

Muscular  (rami  muscular es),  vary  in  number,  and  supply 
the  sartorius  and  vastus  internus; 

Anastomotica  magna  (a.  genu  supremo),  gives  off  two 
branches — superficial,  accompanying  the  long  saphenous  nerve, 
and  deep  branch,  to  the  inner  side  of  knee,  and  supplies  knee 
joint. 

THE  POPLITEAL  ARTERY  (A.  POPLITEA) 

descends!  from  the  opening  in  the  adductor  magnus  to  the  lower 
border  of  the  popliteus  muscle,  passing  behind  the  knee  joint, 
where  it  divides  into  the  anterior  and  posterior  tibial  arteries. 
Its  branches  are : — 

Muscular,  gives  off  two  principal  branches : — 

Superior,  to  flexors  of  thigh  and  vastus  externu's  muscles ; 

Inferior,  or  sural  (aa.  swales),  to  heads  of  gastrocnemius 
and  plantaris. 

Cutaneous,  supplies  the  skin  of  the  calf; 

Superior  external  articular  (a.  genu  superior  lateralis), 
supplies  knee  joint  and  vastus  externus ; 

Superior  internal  articular  (a.  genu  superior  medialis), 
supplies  knee  joint  and  vastus)  internus; 

Azygos  articular  (a.  genu  media),  supplies  the  synovial 
membrane  and  ligaments  of  joints ; 

Inferior  external  articular  (a.  genu  inferior  lateralis),  sup- 
plies knee  joint  and  fibular  head; 

Inferior  internal  articular  (a.  genu  inferior  medialis),  sup- 
plies knee  joint  and  head  of  tibia. 

THE    ANTERIOR    TIBIAL    ARTERY    (A.    TIBIALIS    ANTERIOR) 

descends  from  the  bifurcation  of  the  popliteal  at  the  lower  bor- 
der of  the  popliteus  muscle ;  passes  over  the  upper  border  of  the 
interosseous  membrane,  between  the  two  heads  of  the  tibialis 
posticus,-  and  descends  on  the  anterior  part  of  the  interosseous 
membrane  and  lower  part  of  the  tibia  to  the  ankle  joint,  where 
it  terminates  as  the  dorsalis  pedis. 

In  the  upper  third  of  its  course  it  lies  between  the  tibialis  anticus 
and  extensor  longus  digitorum,  resting  upon  the  interosseous  membrane, 
in  the  middle  third,  between  the  tibialis  anticus  and  extensor  proprius 
pollicrs,  and  at  the  lower  third  it  becomes  more  superficial,  and  lies 
between  the  extensor  proprius  and  extensor  longus  digitorum  tendons. 


THE    HEART    AND    VASCULAR    SYSTEM.  201 

Its  branches  are : — 

Anterior  recurrent  tibial  (a.  recurrens  tibialis  anterior), 
ascends  to  supply  the  front  and  sides  of  the  knee  joint  and 
anastomose  with  the  anastomotica  magna  and  popliteal; 

Posterior  recurrent  tibial  (a.  recurrens  tibialis  posterior), 
is  an  inconstant  artery  that  is  given  off  from  the  anterior  tibial, 
before  the  latter  passes  through  the  interosseous  space.  It  sup- 
plies the  popliteus  muscle,  and  anastomoses  with  some  of  the 
articular  filaments  of  the  popliteal  artery; 

Muscular,  supplying  the  muscles  and  skin  of  the  neighbor- 
ing parts; 

Internal  malleolar  (a.  malleolaris  anterior  medialis),  arises 
two  inches  above  the  ankle  joint,  and  supplies  it  and  the  struc- 
tures on  its  inner  side; 

External  malleolar  (a.  malleolaris  anterior  lateralis),  sup- 
plies the  outer  side  of  the  ankle. 

The  doiisalis  pedis  artery  (a.  tlorsalis  pedis)  extends 
from  the  bend  of  the  ankle,  where  it  is  continuous  with  the 
anterior  tibial,  to  the  first  interosseous  space,  where  it  divides 
into  the  dorsalis  hallucis  and  the  communicating.  Its  branches 
are: — 

Tarsal  (a.  tarsea  lateralis),  supplies  the  tarsal  articulations 
ami  the  extensor  brevis  digitorum  muscle; 

.Metatarsal  (a.  arctiata),  passes  to  the  outer  side  of  the  foot, 
and  gives  off  three  interosseous  branches  to  supply  the  adjacent 
sides  of  the  toes; 

Dorsalis  pollicis  (a.  dorsalis  hallucis),  passes  along  the 
outer  border  of  the  great  toe,  supplying  it; 

Communicating  (ramus  plantaris  profundus),  descends  be- 
tween the  two  heads  of  the  first  dorsal  interosseous  to  complete, 
with  the  external  plantar,  the  plantar  arch; 

Interosseous,  branches  of  the  tarsal  branch,  three  in  num- 
ber. 

THE     POSTERIOR    TIBIAL    ARTERY    (a.    TIBIALIS    POSTERIOR) 

begins  at  the  lower  border  of  the  popliteus  muscle  and  descends 
along  the  posterior  and  tibial  side  of  the  leg  to  the  space  between 
the-  heel  and  the  inner  ankle,  where  it  passes  beneath  the  abduc- 
tor pollicis  and  divides  into  the  internal  and  external  plantar 
arteries. 

Relatione. —  In  tin-  upper  |>art  of  its  course  it  lies  deeply,  being 
covered  by  the  gastrocnemius  and  aoleus  muscle,  but  in  the  lower  part 
it  becomes  more  superficial,  being  covered  only  by  the  skin  and  the 
fascia. 


202 


HUMAN    ANATOMY. 


Its  branches  are : — 

Peroneal  (a.  peroncea),  descends  the  inner  border  of  the 
fibula,  supplying  the  muscles  and  skin  of  that  region  and  the 
back  of  the  ankle ; 

Anterior  peroneal  (ramus  perforans),  a  branch  of  the  pero- 
neal, pierces  the  lower  part  of  the  interosseous  membrane  to 
supply  the  dorsum  and  outer  side  of  the  tarsus;    „ 

Muscular,  supplies  the  posterior  muscles; 

Nutrient  (a.  nwtritia  fib  idee),  supplies  the  tibia,  being  the 
largest  nutrient  artery  in  the  body; 

Communicating  (ramus  communicans) ,  passes  to  the  pero- 
neal; 

Internal  calcanean  (rami  calcanei  mediates),  supplies  the 
inner  side  of  the  sole  and  heel. 

The  internal  plantar  artery  (a.  plantaris  medialis), 
the  smaller  of  the  two,  passes  along  the  inner  side  of  the  foot 
between  the  abductor  pollicis  and  the  flexor  brevis  digitorum  to 
the  inner  border  of  the  great  toe,  anastomosing  with  its  digital 
branch. 

The  external  plantar  artery  (a.  plantaris  lateralis) 
passes  across  the  foot  to  the  base  of  the  fifth  metatarsal  bone, 
where  it  turns  inward  and  crosses  the  foot  to  the  first  inter- 
osseous space,  where  it  anastomoses  with  the  communicating 
branch  of  the  dorsalis  pedis  to  form  the  plantar  arch.  Its 
branches  are : — 

Posterior  perforating  (rami  perforant.es  posteriores) ,  are 
three  branches  which  pass  between  the  heads  of  the  dorsal 
interossei  muscles; 

Digital  branches  (aa.  metatarsece  plantares) — these  are 
four  branches  which  supply  the  adjacent  sides  of  the  three  outer 
toes,  and  the  outer  sides  of  the  second  and  little  toes. 


Arch 

of 
aorta, 


TABLE    OF    THE    ARTERIAL    SYSTEM. 

Aorta. 


Right  coronary. 
Left  coronary. 


Innominate, 

Left   common   carotid, 
Left  subclavian. 


(Right   common       f  External   carotid, 
carotid,  \  Internal  carotid. 

Right  subclavian. 

/  External    carotid, 
I  Internal   carotid. 


THE    HEART    AND    VASCULAR    SYSTEM. 


203 


r  Ilyoid, 

Superiot       i  Superficial   descending  branch, 

thyroid,       1  Superior  laryngeal, 

I  Cricothyroid. 


External 

carotid, 


External 

carotid   - 
continued, 


Lingual, 


Ilyoid, 
Dorsalis  linguse, 


i    Sublingual, 
I    Ranine. 


Facial, 


In  the 
aeckj 

On   the 
face, 


Inferior  or  ascending  palatine, 
tonsillar,  submaxillary,  sub- 
mental,  muscular. 

Muscular,  inferior  labial,  inferior 
coronary.  superior  coronary, 
lateralis  nasi,   angular. 


Occipital,    J 


p  Muscular. 

[    Sternomastoid, 

Auricular, 

Meningeal, 

Arteria  princeps  cervicis, 

Cranial    branches. 


r  Stylomastoid, 
Posterior       j  Auricular, 
auricular,      1  Muscular, 

I  Glandular. 


Ascending      1  Pharyngeal,  external  meningeal, 
pharyngeal     /•'"»'  & 


Pi 


Temporal, 


Transverse  facial, 
Middle   temporal, 
Auricular, 
Anterior  temporal, 
Posterior    temporal. 


Internal 
maxillary, 


Maxillary 
portion, 


'  Tympanic    ( anterior ) , 
Deep  auricular, 
Middle  meningeal, 
Small  meningeal, 
Inferior   dental. 


i  Deep   temporal, 

Pterygoid     J  Pterygoid, 

portion.        1  Masseteric, 

I  Buccal. 


Spheno- 
maxillary 
pari  ion. 


Alveolar, 
Infraorbital, 
.    Tost,  or   ascending   palatine. 

j  Vidian, 
Pterygopalatine, 

N'asal   or  splicnopalatal. 


204 


HUMAN    ANATOMY. 


i 

o 

-a 

X 


ortion9      }  Tympanic -( internal,  or  deep). 


Cavern- 
ous 
portion, 


Arterise  receptaculi, 
Anterior  meningeal. 


Ophthalmic, 


Orbital 
group, 


Ocular 
group, 


Lachrymal, 

Supraorbital, 

Post,  ethmoidal, 

Ant.  ethmoidal, 

Palpebral, 

Frontal, 

Nasal. 

Muscular, 
Ant.  ciliary, 
Short  ciliary, 
Long  ciliary, 
Arteria   centralis 
retinae. 


Cerebral 
portion, 


Verte- 
bral, 


r  Anterior  cerebral, 
j  Middle  cerebral, 
I  Anterior  choroid, 
L  Posterior  communicating. 

Cervical  Branches, 


Thyroid 
axis, 


Lateral  spinal, 
Muscular.  . 

Cranial  Branches, 

, A . 

Posterior  meningeal, 
Anterior  spinal, 
_  Posterior  spinal. 

Inferior  thyroid, 


Superior  scapular, 

( Transversalis  humeri ) , 

Transversalis  colli, 


Transverse, 
Anterior  inferior 
Basilar,  <j       cerebellar, 

Sup.  cerebellar, 
Post,  cerebral. 


'  Laryngeal, 
Tracheal, 
Esophageal, 
Ascend,  cervical, 
Muscular. 

/  Muscular, 

\  Supraacromial, 

/  Superfic.    cervical, 
\  Post,  scapular. 


f  Comes   nervi   phrenici    (superior  phrenic), 
j  Mediastinal, 
Pericardiac, 
Internal!  sternal, 
mam-    -s  Anterior  intercostal, 
mary,      |  Perforating, 

|  Musculophrenic, 
[  Superior  epigastric. 


Superior 
inter- 
costal. 


•  Deep  cervical  branch   (profunda  cervicis), 


THE    HEART    AND    VASCULAR    SYSTEM. 


205 


Axillary,  < 


Acromiothoraeic, 

Superior  thoracic, 
Thoracica  longa, 
Thoracica  alaris. 

f  Dorsalis  scapulae, 
Subscapular,  j  Median  branch. 

Anterior  circumflex, 
Posterior  circumflex. 


'  Superior  prof unda, 
Nutrient  artery, 
Inferior  profunda, 
Brachial,  \  Anastomotica  magna, 
Muscular, 
Radial, 
Ulnar. 


Radial, 


In  foramen, 


In  the  wrist, 


In  the  hand, 


C  Radial  recurrent, 
i  Muscular, 


Superficialis  volse, 


L  Anterior  carpal 

r  Posterior  carpal, 
J  Metacarpal, 
\  Dorsalis  pollicis, 

i.  Dorsalis  indicis. 

r  Princeps   pollicis, 
J  Radialis  indicis, 
\  Perforating, 
[_  Interosseous. 


Ulnar. 


In  the  forearm, 


\   In  the  wrist, 

i 

I   In  the  hand, 


.-Anterior  ulnar  recurrent, 
J  Posterior  ulnar  recurrent, 
i  Interosseous, 

I  Muscular. 

J  Anterior  carpal, 
\  Posterior  carpal. 

f  Dee]),  or  communicating  branch, 
\  Digital. 


206 


HUMAN    ANATOMY. 


Thoracic 
aorta, 


Descending  Aorta. 


Pericardiac, 
Bronchial, 
Esophageal, 
Posterior  mediastinal, 
Intercostal. 


Abdominal 
aorta 


Two  phrenic. 


Celiac  axis,   .. 


Gastric. 


f        Pyloric. 


f     Pancreatico- 
duodenalis 
Hepatic,  J        Gastro-         I  superior, 

1  1     duodenalis,      j  Gastro- 

!  epiploica 

[_  dextra. 


Cystic. 


Splenic 


f    Pan 

,    -I    Gas 
(.    Gas 


Pancreatic, 

troepiploica  sinistra, 
Gastric    (vasa  brevia). 


Superior 
mesenteric, 
Suprarenal,    ■< 
Renal, 


Pancreaticoduodenal  inferior, 
iVasa  intestinalis  tenuis, 
Ileocolic, 
Colica  dextra, 
Colica  media. 


Spermatic. 


Inferior 
mesenteric, 


Colica  sinistra, 

Sigmoid, 

Superior  hemorrhoidal. 
Lumbar    (four  or  five  branches), 
Dorsal  branch, 
Spinal  branch, 
Abdominal  branches, 
Middle  sacral, 


THE    HEART    AND    VASCULAR    SYSTEM. 


207 


c  i 

I 

z 
O 


Branches  to 
ureter,    peritoneum     etc. 


Internal 
iliac, 


Anterior 
trunk. 


External 
iliac, 


Femoral 
i  continuation  i , 


Posterior 
trunk, 


Superior  vesical, 

Middle    vesical, 
Inferior   vesical, 
Middle    hemorrhoidal. 


( Ibturator, 


Within 
pelvis, 


Without 

pelvis, 


Iliac, 

Vesical, 

Pubic. 

r  External 

and 
j    internal 
t  branches. 


Internal 
pudic, 


C  Inferior  hemorrhoidal, 
|    Superficial  perineal, 
J    Transverse    ])erineal, 
1    Bulbourethral, 

Cavernous, 

Dorsal  art'y  of  the  penis. 


Sciatic, 


In    the 


Coccygeal, 

Inferior   gluteal, 

Comitans  nervi  ischiadici, 

Muscular, 

Articular. 


female. 


Uterine, 
Vaginal. 


iliolumbar, 
Lateral  sacral, 
Gluteal. 


_,  f    (  remasteric, 

,)"']1.         Pubic, 
epigastric!    MuBCular< 


Deep       f 

circumflex  -I 

iliac,       ( 


Muscular  branches. 


Superficial  epigastric, 
Superficial  circumflex  iliac, 
Superficial   external   pudic, 
Deep  external  pudic. 


Profunda. 


External  circumflex, 
[nternal  circumflex, 
Three   perforating. 


Muscular, 

\n;i stomol ica   magna, 
Popliteal   i  oonl  inuation), 


208 


HUMAN    ANATOMY. 


Popliteal, 


Anterior 
tibial, 


f  Superior, 


Muscular, 

(_  Interior. 

Cutaneous, 

Superior  external  articular, 

Superior  internal  articular, 

Azygosi  articular, 

Inferior  external  articular, 

Inferior  internal  articular, 

Anterior   tibial, 


Posterior  tibial, 


>  Bifurcation. 


Recurrent  tibial, 
Muscular, 
Internal  malleolar, 
External  malleolar. 


Dorsalis    pedis 
( continuation ) , 


Tarsal,  1         Three 

Metatarsal,     J  interosseous. 
Dorsalis  pollicis  or  hallucis, 
Communicating, 
Interosseous. 


Posterior 
tibial, 


Peroneal, 
Muscular, 
Nutrient, 
Communicating, 
Internal  calcanean, 


Anterior  peroneal. 


Internal  plantar,         j  Bifurcation. 
External  plantar,        J 

(fromexteraal    1  Three  Posterior  perforating, 
(    plantar)  J   F°Ur   **** 


Pulmonary  Artery  (a.  pulmonalis). — The  pulmonary 
artery  carries  venous  blood  from  the  right  ventricle  to  the  lungs. 
It  'is  about  two  inches  in  length,  passes  upward  and  backward 
to  the  left  side  to  the  under  surface  of  the  transverse  portion  of 
the  arch  of  the  aorta,  where  it  divides  into  the  right  and  left 
pulmonary  arteries.  It  is  attached  to  the  under  portion  of  the 
arch  by  a  fibrous  cord,  the  remains  of  the  ductus  arteriosus  of 
fetal  life  (lig  amentum  arteriosum).  The  right  pulmonary 
artery  (ramus  dexter  a.  pulmonalis)  is  larger  and  longer  than 
the  left  (ramus  sinister  a.  pulmonalis),  and  passes  behind  the 
ascending  aorta  and  superior  vena  cava  to  the  root  of  the  right 
lung,  where  it  divides  into  two  branches.  The  left  pulmonary 
artery  passes  in  front  of  the  descending  aorta  and  left  bronchus 
to  the  root  of  the  left  lung,  where  it  divides  into  two  branches. 


THE    HEART    AND    VASCULAR    SYSTEM.  209 

THE    VENOUS    SYSTEM. 

The  venous  system,  like  the  arterial,  consists  of  two  dis- 
tinct sets,  the  systemic  and  pulmonary.  It  is  composed  of  seven 
{ J )  main  trunks  and  their  branches : — 

Systemic.  Pulmonary. 

1.  Coronary  vein;  Four  pulmonary  veins. 

2.  Superior  vena   cava; 
3.  Inferior  vena  cava. 

The  systemic  veins  return  the  venous  blood  from  the  body, 
head  and  extremities  to  the  right  auricle. 

The  portal  vein,  with  its  branches  and  capillaries,  is  an 
appendage  to  the  systemic  set,  collecting  the  venous  blood  from 
the  organs  of  digestion,  i.e.,  stomach,  intestines  and  the  pan- 
creas ;*and  also  from  the  spleen,  and  carrying  it  to  the  liver, 
where  it  breaks  into  capillaries,  and  finally  reaches  the  inferior 
vena  cava  by  means  of  the  hepatic  veins. 

The  pulmonary  veins  (v.  pulmonales)  are  peculiar  in  carry- 
ing arterial  blood  from  the  lungs  to  the  left  auricle. 

Systemic  Veins. — The  coronary  sinus  (sinus  coronarius) 
returns  all  the  blood  from  the  substance  of  the  heart,  except  that 
returned  directly  from  the  walls  of  the  right  auricle  by  the  vena 
Thehesii  |  venoe  cordis  minima).  It  is  a  dilatation  of  the  great 
cardiac  vein,  about  one  inch  in  length,  situated  in  the  posterior 
part  of  the  left  auriculoventricular  groove.  It  opens  into  the 
right  auricle,  its  orifice  being  protected  by  the  coronary  valves, 
and  receives  the  following : — 
Great    cardiac,    or    left    coronary       Right   cardiac   or    small    coronary 

vein   [v.  cordis  magna);  vein   {v.  cordis  parva.)  ; 

Anterior    cardiac    (vv.    cordis   an-      Left  cardiac  vein  (  r.  posterior  ven- 

t,  ,  lores)  ;  triculi  simstri  I  ; 

Middle    cardiac    or    posterior     (v.      Oblique  vein  of   Marshall    (v.   ob- 

cordis  media)  ;  /'7»«  «*r"  sinistn). 

The  superior  vena  cava  (v.  cava  superior)  is  a  short  trunk 
formed  by  the  union  of  the  right  and  Left  innominate  wins.  It 
receives  the  vena  azygos  major  (v.  azygos),  has  no  valves,  and 
is  smaller  in  size  than  the  aorta.  It  ends  in  the  right  auricle, 
receiving  the  blood  from  the  whole  upper  half  of  the  body  and 
the  right  Lymphatic  and  thoracic  duets.     The  left  innominate 

anonyma  sinistra)  passes  to  join  the  superior  cava  m  front 
of  the  greal  arteries  of  the  arch.  The  inferior  thyroid,  the 
internal  mammary  and  vertebra!  veins  follow  closely  the  courses 
0f  the  corresponding  art. Tie.,  and  terminate  in  the  innominate 

Vein. 


u 


210  HUMAN    ANATOMY. 

The  internal  jugular  vein  (v.  jugularis  interna)  is  formed 
by  the  lateral  and  thq  superior  petrosal  sinuses,  descends  at  the 
outer  side  of  the  common  carotid  behind  the  anterior  border  of 
the  sternomastoid  muscle,  and  joins  the  subclavian  vein  to  form 
the  innominate.  At  its  junction  with  the  subclavian  the  left 
internal  jugular  vein  receives  the  thoracic  duct  and  the  right 
internal  jugular  vein  the  right  lymphatic  duct. 

The  Sinuses  of  the  Dura  Matek  (sinus  dwrce  matris) . — 
These  are  venous  channels  analogous  to  veins  between  the 
layers  of  the  dura  mater.  They  are  destitute  of  valves,  follow 
no  vessels,  and  their  inner  coat  is  continuous  with  the  lining 
membrane  of  the  veins.  They  are  divided  into  two  sets;  those 
at  the  back  and  upper  part  of  the  skull  are : — 

Superior  longitudinal,  Lateral  sinuses    (2), 

Inferior   longitudinal,  Occipital  sinus. 

Straight  sinus, 

And  those  of  the  base : — 

Cavernous  (2),  Superior  petrosal   (2), 

Circular,  Transverse       (anterior      occipital, 

Inferior  petrosal    (2),  Leidy ) . 

The  superior  longitudinal  sinus  (sinus  sagittalis  superior) 
arises  at  the  foramen  cecum,  passes  backward  along  the  margin 
of  the  falx  cerebri  to  the  crucial  ridge  of  the  occipital  bone, 
where  it  terminates  in  the  torcular  Herophili  or  confluence  of 
the  sinuses. 

The  inferior  longitudinal  sinus  (sinus  sagittalis  inferior) 
passes  in  the  free  margin  of  the  falx  cerebri. 

The  straight  sinus  (sinus  rectus)  passes  backward  from  the 
junction  of  the  tentorium  with  the  falx  cerebri  to  enter  the 
confluence  of  the  sinuses. 

The  lateral  sinuses  (sinus  transversus)  pass  horizontally 
outward  from  the  torcular  Herophili,  along  the  temporal  bone 
to  the  jugular  foramen,  where  they  terminate  in  the  internal 
jugular  vein. 

The  occipital  sinus  (sinus  occipitalis),  the  smallest  of  all 
the  sinuses,  commences  at  the  margin  of  the  foramen  magnum 
on  either  side  and  passes  backward  to  the  torcular  Herophili. 

The  cavernous  sinuses  (sinus  cavernosus)  pass  from  the 
sphenoidal  fissure  along  either  side  of  the  sella  turcica  to  the 
apex  of  the  petrous  portion  of  the  temporal  bone,  where  they 
join  the  petrosal  sinuses.  They  are  crossed  by  fibrous  bands  or 
offsets  of  the  dura  mater,  and  inclose  the  pathetic,  motor  oculi, 


THE    HEART    AND    VASCULAR    SYSTEM.  gH 

abducens  and  ophthalmic  nerves,  and  the  internal  carotid  artery, 
from  which  they  are  separated  by  the  lining  membrane. 

The  circular  sinus  (sinus  circularis)  is  formed  by  two  small 
vessels  (sinus  intercavernous  anterior  et  sinus  intercavernous 
posterior)  passing  in  front  of  and  behind  the  pituitary  body, 
and  connecting  the  cavernous  sinuses. 

The  inferior  petrosal  sinus  (sinus  petrosus  inferior),  on 
each  side,  runs  in  a  groove  between  the  petrous  portion  of  the 
temporal  bone  and  the  basilar  portion  of  the  occipital,  connect- 
ing the  cavernous  sinuses  with  the  lateral  sinuses. 

The  superior  petrosal  sinus  (sinus  petrosus  superior),  on 
each  side,  passes  along  the  upper  border  of  the  petrous  portion 
of  the  temporal  bone,  connecting  the  cavernous  with  the  lateral 
sinuses*  above. 

The  transverse  or  basilar  (plexus  basilaris)  is  a  small, 
straight  sinus,  connecting  the  inferior  petrosal  and  cavernous 
sinuses. 

Sphenoparietal  sinus  (sinus  sphenoparietal)  runs  in  a 
groove  on  the  under  surface  of  the  lesser  wing  of  the  sphenoid. 
It  takes  origin  from  the  middle  meningeal  veins,  runs  inward. 
passes  through  a  fold  of  dura  mater,  and  usually  receives  the 
anterior  temporal  veins1  from  the  diploe. 

Cerebral  Yeixs  (vence  cerebri). — The  cerebral  veins  con- 
sist of  two  sets — the  superficial,  on  the  surface,  and  the  deep, 
within  the  substance.     They  include: — 

Superficial   (vence  cerebri  externa)  — 

Superior   cerebral   veins    (vv.   cere-       Inferior    cerebral    veins     (re.    cere- 
bri superior es) ,  bri  inferiores). 

Deep — ■ 

Ventricular  veins,  or  venae  Galeni       Veni   corporis    striati    and   choroid 

i  //•.  (inh  iii ;  it.  cert  bri  interna}  | ,  vein  (v.  choroidca). 

The  cerebellar  veins  consist  of  the  superior  superficial  cere- 
bellar veins  (vv.  cerebelli  superiores) ,  and  the  inferior  super- 
ficial cerebellar  veins  (vv.  cerebelli  inferiores)  ;  blood  is  brought 
from  the  interior  to  these  superficial  veins  through  the  deep 
cerebellar  veins. 

Diploic  and  Meningeal  Yeixs. — The  diploic  veins  (vence 
diploica),  five  in  number, — frontal  (v.  diploica  frontalis),  an- 
terior temporal  (v.  diploica  temporalis  anterior),  posterior  tem- 
poral (v.  diploica  temporalis  posterior),  occipital  (v.  diploica 
occipitalis  superior)    -communicate  with  the  sinuses  of  the  brain 

and    with   the  vein-  of  the  dura   mater,  the  scalp  and   orbit. 


212  HUMAN    ANATOMY. 

The  meningeal  veins  (vv.  meningeal)  follow  the  course 
of  the  corresjDonding  arteries,  two  accompanying  each  vessel 
through  its  course,  and  open  into  the  sinuses  of  the  dura  mater. 

The  great  meningeal  veins  terminate  either  in  the  cavern- 
ous sinuses  or  by  emptying  into  the  internal  maxillary  vein. 

The  ophthalmic  superior  vein  (v.  ophthalmica  superior) 
commences  at  the  internal  canthus  of  the  eye  in  an  anastomosis 
with  the  facial,  passes  backward  along  the  inner  part  of  the  orbit, 
through  the  sphenoidal  fissure,  to  empty  into  the  cavernous 
sinuses. 

The  inferior  ophthalmic  vein  (v.  ophtlialmica  inferior) 
arises  from  the  veins  of  the  eyelids  and  the  lachrymal  sac.  It 
runs  backward  along  the  floor  of  the  orbit  and  joins  the  superior 
to  form  a  common  trunk,  or  else  it  enters  the  cavernous  sinus 
by  a  single  opening'. 

The  external  jugular  vein  (v.  jugularis  externa),  smaller 
than  the  internal  jugular,  is  formed  by  the  union  of  the  pos- 
terior auricular  with  the  temporomaxillary  veins;  or  it  may  be 
formed  by  union  with  the  facial.  It  descends  beneath  the 
platysma  muscle  from  the  angle  of  the  jaw  to  the  middle  of  the 
clavicle,  where  it  terminates  by  emptying  into  the  subclavian. 
It  receives  the  following  veins : — 

Anterior  jugular,  Suprascapular, 

Posterior  jugular,  Transverse  cervical. 

The  anterior  facial  vein  (v.  facialis  anterior)  commences 
as  the  angular  at  the  internal  canthus  of  the  eye,  where  it  anas- 
tomoses with  the  ophthalmic  vein,  and  receives  the  frontal  vein. 
About  the  angle  of  the  jaw  it  usually  ends  in  the  internal 
jugular,  but  sometimes  empties  into  the  external  jugular  or 
unites  with  the  temporomaxillary  (v.  facialis  posterior),  to 
form  the  common  facial  vein. 

The  common  facial  vein  (v.  facialis  communis),  formed  by 
the  union  of  anterior  facial  and  the  anterior  division  of  the 
temporomaxillary  vein,  runs  backward  beneath  the  sternomas- 
toid  muscle,  crosses  the  external  carotid  artery,  and  empties  into 
the  internal  jugular.     It  receives: — 

Supraorbital      {v.     supmorbitalis)  Labial, 

and  superior  palpebral,  Submental, 

Nasal  veins,  Submaxillary, 

Inferior  palpebral,  Palatine. 
Buccal  and  masseteric, 

The  temporal  vein,  which  is  known,  as  far  as  the  zygoma, 
as  the  superficial  temporal  vein  {vv.  temporaries  superficiales) ,  is 


THE    HEART    AND    VASCULAR    SYSTEM.  213 

formed  by  the  anterior  temporal,  which  anastomoses  with  the 
frontal,  and  the  posterior  temporal,  which  anastomoses  with  the 
occipital.  It  penetrates  the  parotid  gland  and  forms  the  tem- 
poromaxillary vein  by  uniting  with  the  internal  maxillary.  It 
receives : — 

Articular  veins,  Transverse  facial, 

Anterior  auricular,  Parotid. 

Middle     temporal     [v.     temporalis 
media ) , 

The  internal  maxillary  vein  follows  the  course  of  the 
corresponding  artery,  and  receives  veins  corresponding  to  the 
branches  of  that  vesssl.  Some  of  these  branches  form  the 
pterygoid  plexus.  It  passes  backward  and  unites  with  the  tem- 
poral vein  to  form  the  temporomaxillary. 

The  temporomaxillary  vein  (v.  facialis  posterior),  formed 
by  the  junction  of  the  internal  maxillary  in  part  or  whole  with 
the  temporal,  passes  through  the  parotid  gland  and  receives  the 
posterior  auricular,  to  form  the  external  jugular  vein. 

The  occipital  vein  (v.  occipitalis)  follows  the  course  of  the 
artery,  and  terminates,  usually,  in  the  internal  jugular;  occa- 
sionally, in  the  external  jugular.  The  mastoid  vein,  passing 
through  a  foramen  in  the  mastoid  portion,  connects  it  with  the 
lateral  sinus. 

Veixs  of  the  Tongue  and  Throat. — The  veins  of  the 
tongue  empty  into  the  internal  jugular.  The  lingual  veins  (vv. 
linguales)  begin  near  the  tip  of  the  tongue  under  the  name  of 
the  ranine;  they  commence  on  the  dorsum,  sides  and  under  sur- 
face, and  pass  backward,  receiving  the  dorsal  lingual  vein,  and 
also  the  sublingual  vein,  as  well  as  two  small  veins  (vena' 
comites),  and  terminate  in  the  internal  jugular. 

The  pharyngeal  (vv.  pharyngece) ,  commencing  in  the 
pharyngeal  plexus  (plexus  pharyngeals),  receives  branches  from 
the  brain,  and  terminates  about  on  a  level  with  the  hyoid  bone 
in  the  internal  jugular. 

The  superior  thyroid  (v.  thyreoidea  superioris)  conveys  the 
Mood  from  the  larynx,  trachea  and  thyroid  gland  to  the  interna] 
jugular. 

Veins  of  the  Upper  Extremity. — Superficial  and  deep. 

The  subclavian  vein  (v.  subclavia),  the  continuation  of  the 
axillary,  unites  with  the  interna]  jugular  to  form  the  innomi- 
nate. In  its  passage  over  the  first  rib  it  is  separated  from  the 
artery  by  the  Bcalenue  anticufi  muscle. 


214  HUMAN    ANATOMY. 

Deep  Set. — The  deep  veins  accompany  the  corresponding 
arteries  and  form  the  venae  comites,  one  on  either  side,  except 
the  axillary,  which  has  a  single  vein.  The  valves  are  more 
numerous  in  the  deep  set.  About  the  middle  of  the  arm  one 
of  the  brachial  veins  receives  the  basilic  vein,  one  of  the  larger 
veins  of  the  superficial  set.  The  two  brachial  veins  unite  with 
the  basilic  to  form  the  axillary  vein,  which  in  turn  becomes  the 
subclavian  vein,  receiving  in  its  course  beneath  the  clavicle  the 
cephalic  vein,  a  branch  of  the  superficial  set. 

Superficial  Set. — The  anterior  ulnar  vein  (v.  ulnaris  ante- 
rior) commences  on  the  inner  surface  of  the  hand  and  wrist, 
and  terminates  by  uniting  with  the  posterior  ulnar  (v.  ulnaris 
posterior)  or  the  median  vein.  The  posterior  ulnar  vein  com- 
mences on  the  inner  back  portion  of  the  hand,  anastomosing 
with  the  radial  cutaneous  vein,  and  ascends  to  the  bend  of  the 
elbow,  where  it  becomes  the  basilic  vein; 

The  basilic  vein  (v.  basilica),  from  its  formation  at  the 
bend  of  the  elbow,  ascends  the  inner  side  of  the  biceps,  pierces 
the  fascia,  to  join  the  brachial  vein. 

The  radial  (v.  radialis)  commences  on  the  radial,  dorsal 
aspect  of  the  hand,  and  at  the  bend  of  the  elbow  unites  with 
the  median  cephalic,  to  become  the  cephalic. 

The  cephalic  vein  (v.  cepnalica)  ascends  along  the  outer 
border  of  the  biceps,  and  above  in  the  groove  between  the  deltoid 
and  pectoralis  major,  and  passes  beneath  the  clavicle,  to  end  in 
the  axillary. 

The  median  vein  (v.  mediana  cubiti)  receives  the  blood 
from  the  palmar  surface  of  the  hand  and  the  front  of  the  fore- 
arm, and  usually  divides  into  two  branches — the  median  ce- 
phalic, passing  outward  to  join  the  cephalic,  and  the  median 
basilic,  passing  inward  to  join  the  basilic.  The  median  basilic 
vein,  the  larger,  is  the  one  usually  selected  for  phlebotomy. 

Veins  of  the  Trunk. — The  vena  azygos  major  (v.  azygos) 
commences  in  the  abdomen,  opposite  the  first  or  second  lumbar 
vertebra,  as  a  continuation  upward  of  the  right  ascending  lum- 
bar vein.  It  communicates  with  the  right  renal  and  the  inferior 
vena  cava.  Through  the  lumbar  veins  it  establishes  communi- 
cation with  the  right  common  iliac  vein.  It  passes  through  the 
aortic  opening  of  the  diaphragm,  or  through  an  aperture  in  the 
right  crus,  ascends  on  the  dorsal  vertebras,  arches  over  the  root 
of  the  right  lung,  and  empties  into  the  superior  vena  cava.  It 
is  in  relation  on  its  left  side  with  the  aorta,  thoracic  duct  and 
esophagus.     It  receives 


THE    HEART    AND    VASCULAR    SYSTEM/'  215 

Vena    azygos     minor     ( v.     hernia-  Lower  8  or  9  intercostal  veins, 

zygos),  Right   superior   intercostal   vein. 

Left  upper  azygos  vein  (  vena  liemi-  Right  subcostal  vein, 

azygos  accessoria),  Esophageal    (vv.    nsophagea) , 

Lower  end   of   left   superior   inter-  Right   bronchial, 
costal  vein, 

The  hemiazygos  veins  are  two  in  number : — 

The  vena  azygos  minor  (v.  hemiazygos)  arises  on  the  left 
side,  similarly  to  the  azygos  major,  and  passes  through  the  left 
eras  of  the  diaphragm  and  about  the  eighth  dorsal  vertebra 
crosses  beneath  the  aorta  to  join  the  vena  azygos  major; 

Left  upper  azygos  vein  (vena  hemiazygos  accessoria)  com- 
municates with  the  upper  left  intercostal  vein,  and  terminates 
either  in  the  vena  azygos  minor  or  the  azygos  major. 

The  ascending  or  inferior  cava  (v.  cava  inferior),  formed 
by  the  junction  of  the  common  iliac  veins,  at  the  sides  of  the 
fourth  lumbar  vertebra,  ascends  on  the  right  of  the  aorta, 
grooves  the  posterior  border  of  the  liver,  and  passes  through  the 
quadrate  foramen  in  the  central  tendon  of  the  diaphragm,  and 
ends  in  the  right  auricle,  where  it  is  provided  with  the  Eusta1 
chian  .valve  (valvula  v.  cavce  inferioris  [Eastachii]) .  It 
receives 

Middle  sacral,  Renal  veins  (vv.  renales) — the  left, 

Lumbar    (vv.  lumbales),  the   longer,    crosses    in   front   of 

Spermatic    (vv.  spermatica') ,  from  the  aorta, 

spermatic    plexus     (plexus    pam-  Suprarenal    (vv.   suprarenales) , 

piriformis),  Phrenic    (vv.  phrenica') , 

Ovarian       (vv.      ovmica) ,       from  Hepatic    (2  or  3)     (vv.  hepaticrr) . 

ovarian   plexus    (plexus   arteries 

ovariece) . 

The  portal  vein  (vena  porta?),  about  three  inches  in  length, 
is  formed  by  the  inferior  and  superior  mesenteric,  the  gastric, 
splenic  and  pancreatic  veins.  It  ascends  in  the  right  border  of 
the  lesser  omentum  to  the  transverse  fissure  of  the  liver,  where 
it  divides  into  the  right  and  left.  Its  blood  is  distributed 
through  the  liver,  mixing  with  the  arterial  blood  from  the 
hepatic  artery,  to  be  returned  to  the  inferior  cava  by  the  hepatic 
veins.     It  receives 

The  superior  mesenteric  (v.  mesen-  Cystic    (v.  cystica), 

terioa  superior),  Inferior  mesentery  (v.  mesenterica 

Splenic   (v.  Uenalis),  inferior), 

Ctoronary     (v.    coronaria    ventric-  iliglit  gastroepiploic. 

uli) . 


216  HUMAN    ANATOMY. 

The  portal  vein  and  its  branches  are  destitute  of  valves. 

Veins  op  the  Vertebral  Column. — 1.  The  dorsi-spinal 
veins  (plexus  venosi  vertebrates  externi)  commence  in  an  intri- 
cate network  surrounding  the  vertebral  arches  and  their  proc- 
esses. They  communicate  with  the  intercostal,  vertebral,  intra- 
spinal plexus,  lumbar,  sacral  and  the  superficial  veins  of  the 
back. 

2.  The  intraspinal  or  meningorachidian  veins  (plexus  ve- 
nosi vertebrates  interni)  form  an  intricate  plexus  between  the 
vertebras  and  dura  mater  within  the  spinal  canal.  They  coiit 
sist  of  four  longitudinal  veins — two  in  front  and  two  behind. 
The  anterior  longitudinal  spinal  veins  (sinus  vertebrates  long- 
tudinales),  two  in  number,  extend  along  the  sides  of  the  verte- 
bral bodies  and  opposite  the  bodies  communicate  by  transverse 
trunks,  which,  in  their  passage  beneath  the  vertebral  ligament, 
receive  the  diploic  veins,  or  venae  basis  vertebras  (v.  basiverte- 
bralis),  from  the  interior  of  the  body.  The  posterior  longitu- 
dinal veins,  also  two  in  number,  smaller  than  the  anterior, 
extend  down  the  vertebral  arches  and  are  connected  by  trans- 
verse branches  opposite  the  latter. 

They  receive  the  veins  from  the  spinal  cord  and  its  mem- 
branes. 

3.  The  venae  basis  vertebrae  (v.  basivertebral^)  return  the 
blood  from  the  bodies  of  the  vertebrae  into  the  anterior  intra- 
spinal plexuses. 

The  venae  medulli  spinalis  (vv.  spindles)  are  the  essential 
veins  of  the  cord,  situated  between  the  arachnoid  and  pia  mater. 

Common  Iliac  Veins  (v.  iliaca  communis) . 

Formed  by  the  internal  and  external  iliac  veins  uniting 
opposite  the  sacroiliac  articulation,  pass  beneath  the  right  com- 
mon iliac  artery  to  a  point  a  little  to  the  left  of  the  body  of 
the  last  lumbar  vertebra,  where  they  unite  to  form  the  inferior 
vena  cava.  The  right  is  shorter  and  more  vertical  in  its  course, 
and  both  are  without  valves. 

The  internal  iliac  or  hypogastric  vein  (v.  iliaca  in- 
terna or  v.  hi/pogastrica)  corresponds  to  the  distribution  of  the 
corresponding  artery. 

It  receives  the  following  venae  comites: — 

Gluteal    (vv.  glutece),  Lateral   sacral    (vv.   sacrales    lat- 

Sciatic,  erales)   and 

Obturator    (v.   obturatoriw) ,  Middle  sacral; 

Internal    pudic    (vv.    pudendce   in- 
ternee), 


THE    HEART    AND    VASCULAR    SYSTEM.  217 

and  the  following  plexuses: — 

EZS2SS?  f»—«    EST- }.■»*-* 

The  lateral  and  middle  sacral  form  a  small  plexus — the 
plexus  saeralis. 

The  veins  of  the  rectum,  bladder,  and  generative  organs 
anastomose  freely  and  form  three  plexuses : — 

1.  Hemorrhoidal  plexus  (plexus  hamorrhoidalis)  encircles 
the  lower  part  of  the  rectum,  communicates  with  the  sacral  and 
prostatic  plexuses,  and  veins  from  it  join  the  inferior  mesen- 
teric, internal  iliac  and.  pudic  veins. 

2.  Vesica  prostatic  plexus  surrounds  the  membranous  por- 
tion of  the  urethra,  neck  of  bladder,  prostate  body  and  seminal 
vesicles.     It  communicates  behind  with  the  hemorrhoidal. 

3.  Uterovaginal  plexuses  (plexus  utero vaginalis) . — These 
correspond  in  the  female  with  the  prostatic,  and  communicate 
with  the  vesical  and  hemorrhoidal  plexuses,  the  ovarian,  pudic, 
and.  through  the  uterine  veins  join  the  internal  iliac  veins. 

During  pregnancy  these  veins  or  plexuses  become  greatly 
distended  and  enlarged,  forming  the  uterine  sinuses,  but  retain 
a  straight  course. 

The  pudic  vein  follows  the  same  course  as  the  artery,  com- 
municates with  the  prostatic  and  hemorrhoidal  plexuses,  and 
terminates  in  the  internal  iliac  vein. 

In  the  female  it  originates  from  the  clitoris  and  perineum, 
and  communicates  with  the  vaginal  plexus. 

The  dorsal  vein  of  the  penis  (v.  dorsdlis  penis)  returns  the 
blood  from  the  body  of  that  organ.  It  commences  as  two  venae 
comites  of  the  dorsal  artery,  which  unite  on  the  dorsal  surface 
of  the  root  of  the  penis,  perforates  the  triangular  ligament,  and 
again  divides  to  terminate  in  the  prostatic  plexus. 

The  veins  of  the  corpus  cavemosum  emerge  at  the  lower 
groove,  and  turn  round  their  outer  side  to  join  the  dorsal  vein. 

The  dorsal  vein  of  the  clitoris  has  a  corresponding  origin 
and  course,  and  empties  into  the  vaginal  plexus. 

The  EXTERNAL  iliac  vein  (v.  iliaca  externa,),  the  con- 
tinuation of  the  femoral,  lies  internal  to  the  artery  beneath 
Pouparfs  Ligament,  and  joins  the  interna]  iliac  opposite  the 
sacroiliac  symphysis,  to  form  the  common  iliac  vein,  it  runs 
along  the  brim  of  the  pelvis.  It  receives  at  its  commencement 
the  \ <n;t-  comites  of  the  epigastric  artery  and   the  circumflex 

iliac. 


218  HUMAN   ANATOMY. 

Lower  Extremity. — The  deep  veins  of  the  lower  extrem- 
ity pursue  the  exact  course  of  the  corresponding  arteries,  anas- 
tomosing across  the  vessels  they  accompany,  except  the  femoral, 
which  has  but  one  vein. 

The  popliteal  vein  (v.  poplitea),  formed  by  the  junction  of 
the  anterior  and  posterior  tibial  veins,  ascends)  to  the  lower  mar- 
gin of  Hunter's  canal,  where  it  becomes  the  femoral.  It  receives 
the  articular  veins,  sural  veins  and  the  external  saphenous.  At 
its  commencement  it  lies  internal  and  superficial,  at  the  middle 
of  the  space  directly  behind,  and,  in  the  upper  part  of  its  course, 
external  to  the  artery. 

The  femoral  vein  (v.  femoralis) ,  at  first  behind  the  artery, 
inclines  to  the  inner  side  as  it  ascends^  and  at  Poupart's  liga- 
ment becomes  the  external  iliac.  It  receives  the  profunda 
femoris,  the  internal  saphenous  vein,  and  numerous  muscular 
veins. 

The  superficial  veins  of  the  lower  extremity  consist  of  two 
principal  trunks:  the  external  short  saphenous  (v.  saphena 
parva)  commences  on  the  dorsum  of  the  foot,  passes  behind  the 
outer  malleolus,  ascends  the  leg,  and  pierces  the  deep  fascia  in 
the  popliteal  space,  to  terminate  in  the  popliteal  vein.  The 
long  saphenous  vein  (v.  saphena  magna),  the  larger,  arises 
from  the  dorsum  and  inner  side  of  the  foot,  ascends  the  front 
and  inner  side  of  the  leg  and  thigh,  and  passes  through  the 
saphenous  opening  to  join  the  femoral  vein. 

The;  Pulmonary  Veins  (v.  pulmonales) . — The  pulmonary 
veins  are  four  short,  venous  trunks,  two  from  the  base  of  each 
lung  passing  to  the  left  auricle,  returning  arterial  blood. 

They  differ  from  other  veins  in  the  following  respects : — 

1.  They  are  without  valves; 

2.  They  carry  arterial  blood; 

3.  They  accompany  the  arteries  singly; 

4.  They  are  a  little  larger  than  their  arteries. 

The  right  are  longer  than  the  left,  ano\  pass  from  the  root 
of  the  lung,  on  a  lower  level  than  the  artery,  behind  the  aorta, 
superior  cava  and  right  auricle,  to  enter  the  left  auricle. 


The  Lymphatic  System. 

The  lymphatic  system  includes  the  lymphatic  vessels, 
glands  and  the  lacteals,  and  forms  an  important  accessory  to 
the  blood-vascular   system,   collecting  the  transuded,   unappro- 


THE    HEART    AND    VASCULAR    SYSTEM.  219 

prfated  fluids  of  the  body,  and  the  nutritive  material  derived 
from  the  food,  and  conveying  it  into  the  venous  system. 
It-  consists  of  two  main  trunks : — 

(a)    Thoracic  duct    {ductus  thora-       (b)   Right  lymphatic  duct  (ductus 
us)  •  lymphaticus  dexter)  ; 

and  five  smaller  trunks: — 

1.  Jugular  lymphatic  trunk; 

2.  Subclavian  lymphatic  trunk: 

3.  Bronchomediastinal  lymphatic  trunk; 

4.  Lumbar  lymphatic  trunk; 

5.  Intestinal  lymphatic  trunk. 

Lymphatics  have  been  found  in  nearly  every  organ  and 
texture  in  the  body  except  the  brain,  the  spinal  cord,  cartilage, 
tendon,  eyeball,  placenta,  umbilical  cord,  membranes  of  the 
ovum,  hair,  cutis  and  the  labyrinth  of  the  ear.  They  appear 
to  originate  as  a  fine  capillary  network  interwoven  among  the 
blood  vessels  and  proper  elements  of  the  tissues,  or,  more 
minutely,  in  the  lymph,  perivascular,  and  perineural  spaces.  In 
the  villi  they  commence  as  closed,  club-like  tubes. 

The  lymphatic  capillaries  are  somewhat  larger  than  the 
vascular  capillaries  and  destitute  of  valves.  Their  main  trunks 
pass  through  lymphatic  glands  lying  in  their  course;  before 
doing  which,  however,  they  divide  into  afferent  vessels,  which. 
on  emerging,  nnite  into  a  smaller  number  of  large  vessels,  the 
efferent. 

In  structure,  they  are  composed  of  three  coats — the  exter- 
nal fibroareolar,  middle  muscular,  and  internal  or  endothelial 
and  elastic. 

The  lymphatic  glands  (lymphoglandula)  are  generally  sit- 
uated in  the  course  of  the  blood  vessels,  lymphatic  vessels,  or 
Lacteal  vessels,  being  accumulated  together  in  certain  localities, 
as  the  neck,  abdomen,  axilla,  etc. 

The  lymphatic  glands  and  vessels  are  named  from  the 
regions  they  occupy  or  the  vessels  they  accompany,  and  consist 
usually  of  a  superficial  and  deep  set.  Thus,  we  have  cervical, 
axillary,  mediastinal,  lumbar,  inguinal,  etc.,  and  the  lymphatic 
vessels  corresponding. 

The  lacteals,  or  clujliferous  vessels,  are  the  lymphatic  ves- 
sels of  the  small  intestine,  and  differ  only  from  the  others  in 
carrying  chyle  during  digestion  from  the  intestines  to  the 
thoracic  duct. 

The  thorai  i<  di  ct  (ductus  thoradous)  is  formed  by  the 
junction  of  the  two  Lumbar  Lymphatic  trunks  with  the  intestinal 


220  HUMAN    ANATOMY. 

lymphatic  trunk,  in  front  of  the  second  lumbar  vertrebra, 
between  the  aorta  and  inferior  vena  cava,  as  the  receptaculum 
chyli,  or  cistern  of  Pecquet  (cistema  chyli).  This  receptacle 
is  about  one  to  two  inches  long  and  a  quarter  of  an  inch  wide. 
From  its. origin  the  thoracic  duct  ascends  through  the  abdomen, 
passes  through  the  aortic  orifice  in  the  diaphragm,  and  ascends 
behind  the  esophagus  between  the  aorta  and  azygos  vein  to  the 
fourth  dorsal  vertebra,  where  it  passes  to  the  left  beneath  the 
aorta,  and  ascends  between  the  esophagus  and  the  left  sub- 
clavian artery  to  the  last  cervical  vertebra,  where  it  arches  for- 
ward, outward  and  downward  to  enter  the  junction  of  the 
subclavian  and  the  left  internal  jugular  vein  at  its  posterior 
aspect.  Its  orifice  is  protected  by  a  pair  of-  valves.  It  receives 
all  the  lymphatic  vessels  below  the  diaphragm,  those  of  the  left 
side  of  the  head,  neck  and  left  upper  extremity. 

The  eight  lymphatic  duct  (ductus  lymphaticus  dexter) 
is  about  half  an  inch  long  and  one-twelfth  inch  wide.  It  empties 
in  a  corresponding  manner  on  the  right  side  to  the  thoracic 
duct.  It  receives  all  the  lymphatics  of  the  right  side  of  the 
thorax,  neck,  head  and  right  upper  extremity. 

Lymphatics  op  the  Head  and  Neck. — The  substance  of 
the  brain  is  probably  destitute  of  lymphatics,  but  they  are  very 
numerous  in  the  pia  mater  and  choroid  plexuses  of  the  lateral 
ventricles,  and  pursue  the  same  course  as  the  principal  veins,  to 
emerge  at  the  base  through  the  various  foramina,  to  terminate 
in  the  deep  cervical  glands.  The  occipital  lymphatic  vessels 
terminate  in  the  posterior  auricular,  or  retroauricular  or  mas- 
toid glands  (lympho glandules  auriculares  posteriores) ,  and  occip- 
ital or  suboccipital  glands  (lympho  glanduke  occipital es)  .  The 
temporal  lymphatic  vessels  terminate  in  the  anterior  or  auric- 
ular glands.  The  lymphatics  of  the  face  are  superficial  and 
deep.  The  superficial  lymphatics  are  numerous,  and  terminate 
in  the  submaxillary  glands,  six  or  more  in  number;  the  deep 
lymphatics  accompany  the  branches  of  the  internal  maxillary 
artery,  and  terminate  in  the  deep  cervical  and  deep  parotid 
glands  about  the  ramus  of  the  jaw. 

Lymphatics  of  the  Upper  Extremity. — Lymphatics  of 
the  upper  extremity  are  composed  of  two  sets,  the  superficial 
and  deep.  The  superficial  lymphatic  glands  are  few  in  num- 
ber, one  or  two  only  being  situated  at  the  internal  condyle  of 
the  humerus.  The  deep  lymphatic  glands  lie  along  the  course 
of  the  vessels,  and  communicate  with  the  axillary  glands.  All 
of  these  glands  unite  in  the  deep  axillary  glands  (lympho- 
glandulw  axillares),  about  eight  to  ten  in  number,  which  com- 


THE    HEART    AND    VASCULAB    SYSTEM.  -j-j] 

municate  with  the  deep  cervical  glands,  and  through  them 
empty  into  the  subclavian  lymphatic  trunk,  to  end  finally  in 
the  thoracic  or"  right  lymphatic  duct.  The  superficial  and  deep 
vessels  of  the  thorax,  the  former  in  the  skin,  the  latter  from 
the  mammary  glands,  pectoral  and  other  muscles,  for  the  most 
part,  pass  to  the  axilla,  a  few  only  terminating  in  the  glands 
below  the  clavicle. 

The  Cavity  of  the  Thorax.- — The  intercostal  lymphatic 
vessels,  derived  from  the  side  of  the  abdomen  and  thorax, 
pleura?,  diaphragm,  spinal  canal,  muscles  of  the  back,  etc.,  fol- 
low the  course  of  the  veins,  traverse  fifteen  to  twenty  intercostal 
glands  (tymphoglandulw  intercostales)  near  the  heads  of  the 
ribs,  and  terminate  in  the  thoracic  duct.  The  posterior  medias- 
tinal glands  {lymphoglandvlm  mediastinales  posteriores)  are 
between  the  intercostal  glands,  and  communicate  with  them, 
receiving  vessels  from  the  pericardium,  esophagus  and 
diaphragm.  Some  of  the  efi'erent  vessels  end  in  the  bronchial 
glands,  others  in  the  thoracic  duct.  The  anterior  mediastinal 
lymphatic  vessels  (lymplioglandulm  mediastinales  anteriores) 
are  derived  from  the  anterior  wall  of  the  abdomen  and  thorax, 
the  diaphragm,  pericardium,  upper  surface  of  the  liver,  heart 
and  thymus  gland.  They  traverse  about  eighteen  to  twenty 
anterior  mediastinal  glands,  situated  in  the  course  of  the  inter- 
nal mammary  vein,  pericardium,  and  great  vessels  of  the  heart, 
and  terminate  in  thoracic  and  right  lymphatic  ducts.  The 
pulmonary  lymphatic  vessels  consist  of  a  superficial  and  deep 
set,  traversing  in  the  last  part  of  their  course  the  pulmonary 
glands.  The  bronchial  glands  are  twenty  or  more  glands  at  the 
bifurcation  of  the  trachea  and  root  of  the  lungs,  and  receive  the 
lymphatic  vessels  of  the  lungs  and  bronchi.  They  become  pig- 
mented, and  are  often  the  seat  of  disease.  Their  efferent  vessels 
terminate  on  the  right  side  in  the  right  lymphatic  duct,  either 
directly  or  by  forming  the  bronchomediastinal  trunk,  and  on 
the  left  side  in  the  thoracic  duct. 

Lowes  Extremity  and  Pelvis. — The  superficial  lym- 
phatic vessels  from  the  back  of  the  foot  follow  the  course  of 
the  long  saphenous  vein,  passing  to  the  superficial  inguinal 
glands  {lymplio'.itnmlnbi'  in/j/dnales  supcrficiales)  ;  and  (hose 
from  the  sole  of  the*  foot  follow  the  short  saphenous  vein,  join- 
ing the  deep  set  in  the  popliteal  space.  The  deep  lymphatic 
vessels  follow  the;  deep  veins,  traverse  two  to  four  popliteal 
glands  {lymphoglandutcB  />ni<lile<r) .  and  join  flic  dec])  inguinal 
glands  (lymphoglandulce  inguinales  profunda*!).  The  deep  lym- 
phatic glanda  in  the  pelvis  consist  of  three  sets:    the  external 


222  HUMAN    ANATOMY. 

iliac,  around  the  external  iliac  vessels;  the  internal  iliac,  around 
the  internal  iliac  vessels ;  and  the  sacral  glands,  on  the  anterior 
surface,  and  in  the  mesorectal  folds. 

Lymphatics  of  the  Abdomen. — The  lymphatic  vessels  of 
the  external  and  internal  iliac  glands  enter  the  lumbar  glands, 
twenty-five  or  more  in  number,  situated  upon  the  vertebrae,  the 
origin  of  the  diaphragm,  the  psoas  and  quadratus  lumborum 
muscles  and  the  great  blood  vessels.  They  receive  vessels  from 
the  kidneys,  ureters,  loins,  suprarenal  bodies,  ovaries  and  testi- 
cles, and  form  lumbar  lymphatic  trunks,  which  ascend  to  join 
the  thoracic  duct  or  receptaculum  chyli.  The  lymphatic  vessels 
of  the  stomach  follow  the  general  course  of  the  blood  vessels, 
They  consist  of  three  groups :  the  first,  along  the  lesser  curva- 
ture, passing  to  the  glands  along  the  pylorus ;  the  second,  at  the 
great  end  of  the  stomach,  passing  to  the  splenic  lymphatic 
glands ;  and  the  third,  at  the  greater  curvature,  passing  to  one 
of  the  principal  lacteal  vessels.  The  lymphatics  of  the  small 
intestine  are  called  also  lacteals.  They  pass  between  the  layers 
of  the  mesentery  and  traverse  a  large  number  of  mesenteric 
glands,  arranged  irregularly  into  three  rows.  The  lymphatic 
vessels  of  the  large  intestine  traverse  the  mesocolic  glands,  about 
thirty  in  number,  and  pass  into  the  superior  mesenteric  glands. 
The  vessels  from  the  spleen  and  pancreas  follow  the  course  of 
the  splenic  vein,  traverse  a  number  of  the  glands,  to  end  in  the 
celiac  glands.  The  lymphatics  of  the  liver  consist  of  superficial 
and  deep,' and  are  very  extensive,  both  on  the  upper  and  lower 
surfaces.  They  terminate  in  the  right  lymphatic  duct,  the 
glands  of  the  gastrohepatic  omentum,  the  anterior  mediastinal 
glands,  the  esophageal  glands,  the  glands  of  the  lesser  curvature 
and  of  the  thoracic  duct.  The  deep  lymphatics  follow  the 
course  of  the  portal  vein  and  hepatic  artery  and  duct,  and, 
emerging,  join,  one  of  the  lacteal  vessels  before  it  enters  into 
the  thoracic  duct.  The  celiac  glands,  fifteen  or  twenty  in  num- 
ber, are  situated  behind  the  pancreas  and  duodenum,  the  aorta, 
portal  vein,  celiac  and  superior  mesenteric  vessels.  Their  effer- 
ent vessels  form  the  intestinal  lymphatic  trunk  and  empty  into 
receptaculum  chyli. 


THE  ALIMENTARY  APPARATUS. 


The  alimentary  apparatus  consists  of  the  alimentary  canal 
and  of  certain  accessory  organs. 

The  former  is  a  musculo-membranous  canal  about  thirty  feet 
in  length,  extending  from  the  mouth  to  the  anus,  and  comprises : 
first,  the  organs  of  deglutition,  consisting  of  the  mouth,  pharynx, 
and  oesophagus;  and,  second,  the  organs  of  digestion,  consisting 
of  the  stomach  and  small  and  large  intestines.  'It  is  lined 
throughout  by  mucous  membrane.  The  accessory  organs  com- 
prise the  teeth,  salivary  glands,  liver,  and  pancreas. 


Alimentary 
canal, 


Alimentary  Apparatus. 

-{ 


Mouth, 
'  Organs  of  deglutition,    -j   Pharynx, 

(Esophagus. 


_  Organs  of  digestion, 


Stomach, 

Duodenum, 
Small  intestine,  -j   Jejunum, 

Ileum. 


'  Teeth, 


tine,  < 
tine,   -I 


Caecum, 
__  Large  intestine,   ■{   Colon, 
Rectum. 


Accessory 
organs, 


Salivary  glands, 

Liver, 
Pancreas. 


f  Pa 

\   Su 
(  Su 


Parotid, 

bmaxillary, 
Sublingual. 


The  mouth  (cavum  oris)  is  an  oval  cavity  in  which  mas- 
tication takes  place  preparatory  to  deglutition.  It  is  placed  at 
the  entrance  of  the  alimentary  canal,  is  bounded  laterally  by 
the  alveolar  processes  of  the  upper  and  lower  jaws  and  cheeks; 
above  by  the  upper  teeth  and  hard  palate;  below  by  the  tongue, 
the  lower  j;iw,  the  mucous  membrane  between,  and  the  lower 
teeth  ;  in  front  by  the  lips;  and  behind  by  fauces  and  soft  palate. 
It  terminates  posteriorly  at  the  anterior  pillars  of  the  fauces, 
through  the  fauces  into  the  pharynx. 

(223) 


224  HUMAN    ANATOMY. 

It  is  invested  throughout  (except  on  the  teeth)  with  highly 
vascular  mucous  membrane  covered  with  stratified  squamous 
epithelium  containing  conical  papillae. 

It  presents  for  examination  the  following  parts: — 

The  Teeth  (dentes). — The  teeth  are  firmly  implanted 
within  the  alveoli  of  the  jaws  (alveoli  dentales)  and  surrounded 
by  the  gums. 

The  gums  (gingiva)  are  composed  of  dense  fibrous  tissue, 
covered  by  smooth,  vascular,  mucous  membrane  of  slight  sen- 
sibility. This  fibrous  tissue  is  continuous  with  the  periosteum 
of  the  jaws,  and  forms  about  the  neck  of  the  teeth  a  constricted 
ring — the  dental  ligament. 

There  are  four  kinds  of  teeth — incisors,  canines  or  cuspids, 
premolars  or  bicuspids,  and  molars.  Man  is  provided  with  two 
sets  of  teeth,  the  temporary,  deciduous,  or  milk  teeth,  which 
appear  in  childhood,  and  the  permanent,  which  appear  after 
the  shedding  of  the  milk  teeth,  and  last  until  old  age. 

The  temporary  or  deciduous  teeth  (dentes  decidui)  are 
twenty  in  number,  ten  in  each  jaw;  or  five  in  each  side  of  each 
jaw:— 

Two  incisors,,  one  canine,  and  two  molars. 

The  permanent  teeth  (dentes  permanentes)  are  thirty-two 
in  number,  sixteen  in  each  jaw,  or  eight  in  each  side  of  each 
jaw  (arcus  dentalis  superior  or  areas  dentalis  inferior)  :— 

Two  incisors,  one  canine,  two  bicuspids,  three  molars. 

Each  tooth  consists  of  three  parts : — 

Crown,  or  body  (corona  dentis),  the  enameled  portion 
above  the  gum;  neck  (collum  dentis),  the  constricted  portion 
between  the  crown  and  root;  root,  or  fang  (radix  dentis), 
within  the  alveolus,  and  covered  with  cement. 

Characteristics. — Incisors  (dentes  incisivi),  or  cutting,  are 
so-called  from  their  wedge-shaped,  chisel-like  crown,  being 
adapted  for  biting  or  cutting  the  food.  The  fang  is  long,  single, 
conical  and  compressed  at  the  sides. 

Cuspids,  or  canines  (dentes  canini),  have  been  so  named 
from  their  conspicuous  character  in  the  canine  or  dog  tribe. 

The  crown  is  large,  conical,  convex  in  front,  and  beveled 
behind.  The  fang  is  single,  longest  and  thickest  of  all  the 
teeth. 

Bicuspids,  or  premolars  (dentes  premolares).  The  crown 
has  a  pair  of  projecting  tubercles  or  cusps.  Fang  is  conical, 
single,  but  deeply  grooved,  indicating  a  disposition  to  bifurcate. 

Molars  (dentes  molares),  commonly  known  as  grinders  or 
'jaw   teeth.     Crown,  broad,   quadrilateral,  with   four  cusps   in 


THE  ALIMENTARY  APPARATUS.  225 

upper,  five  in  lower  molars.  Lower  molars  have  usually  a  pair 
of  fangs  placed  laterally;  the  upper,  three  fangs,  two  external 
and  one  internal. 

The  last  or  third  molar  has  but  one  fang  (with  a  tendency 
to  divide  into  the  same  number  of  roots  as  the  other  molars), 
and  is  known  as  the  dens  sapiential,  or  "wisdom  tooth"  {dens 
serotini),  from  its  late  appearance. 

Structure. — On  section  a  tooth  consists  of  two  portions,  the 
pulp  cavity  (vavum  dentis)  and  the  solid  portion  surrounding  it. 

The  solid  portion  consists  of  three  structures,  dentine  or 
ivory,  which  forms  the  principal  mass  of  the  tooth;  enamel, 
which  covers  the  crown,  and  cement,  which  covers  the  surface 
of  the  fang. 

Dentine  or  ivory  {substantia?  eburnea),  resembles  bone,  but 
differs  from  it  in  composition  and  structure,  consisting  of 
twenty-eight  parts  animal  and  seventy-two  parts  mineral  mat- 
ter, and  being  made  up  of  minute  tubuli  held  together  by  the 
intertubular  substance. 

The  dental  tubuli  {canaliculi  dental es)  are  minute  cylin- 
drical canals  /4soo  °f  an  inch  m  diameter.  They  pass  in  a 
spiral  direction  from  the  pulp  cavity  to  the  periphery. 

Enamel  {substantia  adamaniina),  the  hardest  and  densest 
of  all  organized  bodies,  contains  but  3.5  per  cent,  animal  matter, 
and  is  composed  of  minute  hexagonal  rods  {prismata  adaman- 
iina) %-,oo  of  an  inch  in  diameter,  placed  at  right  angles  to 
the  surface  of  the  dentine.  The  external  surface  of  unworn 
enamel  can  be  separated  as  a  thin,  homogeneous  membrane, 
Nasmyth's  membrane  {cuticula  dentis). 

Cement,  or  crusta  petrosa  {substantia  ossea),  is  a  thin 
layer  of  true  bone  with  canaliculi  and  lacunas,  disposed  on  the 
surface  of  the  fang. 

The  pulp  cavity  {cavum  dentis)  is  a  cavity  within  the  base 
of  the  crown,  continuous  with  a  canal  in  the  center  of  the  fang, 
and  open  at  the  apex  of  the  fang  {canal  radicis  dentis)  for  the 
entrance  of  vessels  and  nerves.  It  is  filled  with  dental  pulp 
{put pa  dentis). 

Den  I a /  pulp  consists  of  two  kinds  of  cells,  the  fusiform  and 
the  columnar,  or  odontoblasts  of  Waldeyer,  held  together  by 
loose  connective  tissue.  It  is  soft,  vascular  and  highly  sensi- 
tive. The  nerves  are  both  medullated  and  non-medullated,  and 
form  a  rich  plexus  beneath  the  odontoblastic  layer.  The  ter- 
minal fibrils  probably  unite  with  these  cells,  but  the  exact  dis- 
tribution is  still  unsettled. 

15 


226 


HUMAN    ANATOMY. 


Development — Temporary. — They  are  formed  very  early, 
seven  to  eleven  weeks,  in  the  primitive  dental  groove  by  an 
involution  of  the  epithelium  of  the  oral  cavity  covering  the 
maxillary  arches  into  the  blastema  or  corium  and  connective 
tissue  below,  the  former  giving  the  enamel,  the  latter  the  cement 
and  dentine. 

The  enamel  comes  from  the  enamel  germ,  a  mass  of  epi- 
thelial cells,  descending  into  the  dental  groove  until  it  meets 
the  dentine  papilla  (papilla  dentis),  a  vascular  growth  extend- 
ing upward  from  the  connective  tissue,  upon  which  it  forms  a 


C.In. 
6-8 

Fig.  86. 

Temporary   teeth. 

cap.  A  vascular  membrane  inclosing  the  enamel  germ  then 
extends  itself — as  the  dental  sac — upon  the  united  papilla  and 
enamel  germ  and  cuts  the  latter  off  from  its  earlier  epithelial 
structure.     The  cells  become  differentiated  and  finally  calcify. 

The  dentine  is  formed  by  the  development  of  odontoblasts 
in  the  periphery  of  the  papilla  in  a  similar  manner  to  the 
development  of  osteoblasts  in  bone. 

The  cement  is  developed  from  the  wall  of  the  dental  sac 
by  the  intramembranous  process  of  ossification. 

Permanent.- — The  successional  permanent  teeth,  or  those 
replacing  the  temporary,  are  developed  in  a  different  manner 
from  the  superadded,  or  three  molars  in  each  side  of  each  jaw. 

The  former  are  developed  similarly  to  the  temporary  teeth, 
but  in  a  secondary  dental  groove,  from  which,  after  their  for- 
mation, they  recede  behind  the  germs  of  the  temporary  teeth, 


THE  ALIMENTARY  APPARATUS. 


227 


inclosed  in  sacs.  The  molars,  or  superadded  teeth,  however,  are 
formed  by  extensions  backward  of  a  portion  of  the  enamel  germ 
of  the  tooth  immediately  in  front. 

Eruption,  or  "cutting  of  the  teeth,"  takes  place  by  the 
growth  of  the  fang,  the  gums  being  absorbed  by  the  pressure 
of  the  advancing  crown.  The  development  of  the  fangs  of  the 
permanent  causes  the  ahsorption  of  the  fangs  of  the  temporary 
teeth  through  the  agency  of  the  odontoclasts*,  multinucleated 
cells  corresponding  to  the  osteoclasts  of  bone. 


16-20 


Fig.  ST. 
Permanent    teeth. 


The  eruption  of  the  temporary  teeth  takes  place  in  months 
in  the  order  shown  in  Fig.  86,  the  lower  preceding  by  a  short 
time  the  upper  (according  to  Dr.  C.  X.  Pierce,  in  "American 
m  of  Dentistry").  The  order  of  the  eruptions  is:  first 
the  lower  central  incisors,  the  upper  central  incisors,  lateral 
incisors,  upper  and  lower,  first  molars,  followed  by  the  canines 
or  cuspids,  and  ending  with  the  second  molars. 

The  eruption  of  permanent  teeth  takes  place  in  years  as  in 
Fig.  87,  the  order  of  the  eruptions  being,  firs!  the  "flrsl  or  sixth 
pear  molar/'  followed  by  Hie  firs!  central  incisors,  four  lateral 
incisors,  four  first  bicuspids,  four  second  bicuspids,  the  first 
canines  or  cuspids,  the  four  second  molars,  and  ending  with  the 
four  third  molars  or  "wisdom  teeth.''' 


228  HUMAN    ANATOMY. 

About  the  sixth  year  the  jaws  contain  the  temporary  teeth 
fully  erupted,  and  the  crowns  of  all  the  permanent  teeth  except 
the  four  wisdom  teeth,  in  all  forty-eight. 

It  should  be  noted  that  the  first  permanent  or  "sixth-year" 
molar  is  erupted  before  any  of  the  permanent  teeth,  and  that 
the  second  bicuspid  takes  the  place  of  the  second  temporary  • 
molar. 

Vessels  and  Nerves  of  the  Teeth. — The  arteries  of  the  upper 
teeth  are  derived  from  the  anterior  dental  branches  of  infra- 
orbital and  posterior  or  alveolar  dental  branches  of  the  internal 
maxillary;  of  the  lower  teeth,  from  the  inferior  dental  branch 
of  the  internal  maxillary. 

The  nerves  are  distributed  to  the  upper  teeth  from  the 
anterior  and  posterior  dental  branches  of  the  superior  maxillary 
(second  division  of  fifth  cranial  nerve),  and  to  the  lower  teeth 
from  the  inferior  maxillary  (third  division  of  fifth  cranial 
nerve). 

Soft  palate  (palatum  molle)  is  a  movable  fold  of  mucous 
membrane  suspended  from  the  posterior  border  of  the  hard 
palate,  and'  inclosing  an  aponeurosis,  vessels,  nerves,  glands  and 
the  following  muscles  on  each  side ;  tensor  palati,  levator  palati, 
palatoglossus,  palatopharyngeus  and  azygos  uvulse,  the  latter 
uniting  with  its  fellow  to  form  the  uvula  (uvula  palatina). 

Hard  palate  (palatum  durum)  is  formed  by  the  palatal 
process  of  the  superior  maxillary  and  the  palate  bone,  and  cov- 
ered by  a  thick,  dense  structure  composed  of  mucous  membrane 
and  periosteum  combined.  It  forms  the  roof  of  the  mouth,  and 
presents  a  median  raphe  (raphe  palati)  and  corrugated  surface 
(plicce  palatina?  transversa?) . 

Anterior  pillar  of  the  fauces  (arcus  glossopalatinus)  is  a 
fold  of  mucous  membrane  arching  downward  and  forward  from 
the  base  of  the  uvula  to  the  base  of  the  tongue,  and  inclosing 
the  palatoglossus  muscles. 

Posterior  pillar  of  the  fauces  (arcus  pliaryngopalatinus) 
is  a  similar  fold  arching  downward  and  backward  from  the  base 
of  the  uvula  to  the  sides  of  the  pharynx,  and  inclosing  the 
palatopharyngei  muscles. 

The  tonsils  (tonsilla  palatina),  or  amygdalae,  are  small, 
almond-shaped,  glandular  bodies  situated  on  each  side  of  the 
fauces  between  the  anterior  and  posterior  pillars.  They  rest 
upon  the  superior  constrictor  of  the  pharynx,  which  separates 
them  from  the  ascending  pharyngeal  and  internal  carotid  ar- 
teries. They  are  composed  of  numerous  follicles  (fossulm  ton- 
sillares)    (lined  by  closed  capsules  containing  adenoid  tissue), 


THE  ALIMENTARY  APPARATUS.  229 

which  contain  a  thick,  grayish  secretion  and  open  on  the  surface 
of  the  gland  by  a  dozen  or  more  orifices. 

The  arteries  to  the  tonsil  are  from  the  tonsillar  and  as- 
cending palatine  of  the  facial,  dorsalis  linguae  from,  the  lin- 
gual, ascending  pharyngeal  from  external  carotid,  branch  from 
small  meningeal,  and  descending  palatine  branch  of  internal 
maxillary. 

The  nerves  are  from  glossopharyngeal  and  Meckel's  gan- 
glion. 

The  Salivary  (i lands. — The  salivary  glands  communi- 
cating with  the  month  are  three:  the  parotid,  submaxillary 
and  sublingual. 

The  parotid  gland  (glandules  parotis),  so  called  from  its 
location  near  the  ear,  is  the  largest,  weighing  from  a  half  to 
one  ounce.  It  occupies  the  space  in  front  of  the  ear,  bounded 
below  by  the  angle  of  the  jaw,  and  a  line  extended  from  it  to 
the  mastoid  process,  above  by  the  zygoma,  in  front  by  the 
masseter  muscle,  and  behind  by  the  mastoid  process,  the  exter- 
nal meatus  and  the  digastric  muscle.  The  external  carotid 
artery,  the  temporomaxillary  vein,  the  facial  nerve  and  the 
great  auricular  nerve  pass  through  it. 

The  duct  of  the  parotid  gland  (ductus  parotideus  [Steno- 
nis~\),  Steno's  or  Stenson's  duct,  empties  its  secretion  into  the 
mouth.  It  is  about  two  and  a  half  inches  in  length,  of  the 
diameter  of  a  crow's  quill,  and  crosses  the  face  upon  the  mas- 
seter muscle,  through  the  substance  of  the  buccinator  muscle, 
in  the  direction  of  an  imaginary  line  drawn  about  a  finger's 
breadth  below  the  zygoma,  from  the  lower  part  of  the  ear  to 
midway  between  the  ala  of  the  nose  and  the  margin  of  the  upper 
lip,  to  open  about  the  position  of  the  second  molar  tooth  of  the 
upper  jaw. 

Its  arteries  are  branches  of  the  external  carotid.  The 
veins  empty  into  the  external  jugular.  The  lymphatics  empty 
into  the  superficial  and  deep  cervical  glands,  and  the  nerves  are 
derived  from  the  facial,  from  the  superficial  temporal  branches 
of  the  great  auricular,  the  auriculotemporal  ami  sympathetic. 

The  submaxillary  gland  (glandula  submaxillaris)  occupies 
the  submaxillary  fossa  on  the  inferior  surface  of  the  inferior 
maxilla,  within  the  submaxillary  triangle  of  the  neck.  Tbc 
facial    artery  grooves    itfl    upper  and    posterior  border,   ami    if    is 

separated  behind  from  the  parotid  .gland  by  the  stylomaxillary 
ligament.  The  dud  of  the  submaxillary  gland,  or  Wharton's 
dud  (ductus  submaxUlarw  [Whartoni]),  aboul  two  inches  in 
length,  passes  forward  between  the  hyoglossus,  geniohyoglossue 


230  HUMAN    ANATOMY.     . 

and  mylohyoid  muscles,  to  open  at  the  side  of  the  frsenum  linguae 
in  a  small  papilla  {caruncula  sublingualis). 

Its  arteries  are  from  the  facial  and  lingual;  the  veins  fol- 
low the  course  of  the  corresponding  arteries;  the  nerves  are 
from  the  submaxillary  ganglion,  the  sympathetic  and  the  my- 
lohyoid branch  of  the  inferior  dental. 

The  sublingual  gland  (glandula  sublingualis) ,  the  smallest, 
lies  on  the  floor  of  the  mouth,  at  the  side  of  the  frsenum  linguae, 
beneath  the  mucus  membrane.  Its  ducts,  called  the  ducts  of 
Eivinus  (ductus  sublingualis  minor  es),  from  eight  to  twenty, 
open  on  the  mucous  membrane.  One  of  them,  the  longest, 
called  the  duct  of  Bartholin  (ductus  sublingualis  major),  joins 
Wharton's  duct.  Its  arteries  are  from  the  submental  and  sub- 
lingual.   The  nerves  are  branches  from  the  gustatory. 

Besides  these  glands,  the  mucous  membrane  of  the  mouth 
is  plentifully  supplied  with  mucous  glands. 

The  pharynx  is  a  musculomembranous  sac,  extending 
from*  the  basilar  process  of  the  occipital  bone  above  to  the  level 
of  the  fifth  cervical  vertebra  or  the  cricoid  cartilage  below.  It 
is  about  four  and  a  half  inches  in  length.  It  has  communicat- 
ing with  it  seven  openings : — 

Two  posterior  nares,  Larynx, 

Two   Eustachian   tubes,  Esophagus, 

Mouth. 

It  is  composed  of  three  coats :—  . 

1.  Fibrous  coat,  or  pharyngeal  aponeurosis,  attached  above 
to  the  pharyngeal  spine  of  the  basilar  jtrocess  of  the  occipital 
bone ;  it  affords  attachment  in  the  median  line  to  the  constrictor 
muscles  of  the  pharynx. 

2.  Mucous  coat  (tunica  mucosa),  continuous  with  that  of 
the  various  openings.  It  is  covered  in  its  upper  part  with 
columnar  ciliated  epithelium,  as  low  as  the  floor  of  the  nares, 
below  which  it  is  squamous.  It  contains  numerous  racemose 
glands  (glandules  pharyngeal),  crypts,  and"  lymphoid  structure 
similar  to  the  tonsils,  a  mass  of  which,  between  the  Eustachian 
tubes,  has  been  called  the  "pharyngeal  tonsil." 

3.  Muscular  coat  (tunica  muscularis  pharyngis),  consists 
of  the  three  pharyngeal  constrictors,  the  palatopharyngeus  and 
the  stylopharyngeus.     (Vidje  Muscles.) 

Arteries  are  from  the  inferior  palatine,  pharyngeal  and 
thyroid  arteries.  Nerves  are  branches  of  the  pneumogastric, 
glossopharyngeal  and  sympathetic. 


THE  ALIMENTARY  APPARATUS. 


231 


The  esophagus,  or  cili.ht.  is  a  museulomembranous  tube 
about  nine  inches  long  and  less  tban  one  inch  in  diameter,  flat- 
tened from  before  backward,  and  extending  from  the  pharynx  to 
the  stomach  or  from  the  level  of  the  fifth  cervical  to  the  ninth 

dorsal  vertebra. 

Relations. —  In  the  nock  the  trachea  is  in  front,  the  common  carot- 
ids on  either  side,   and   in   the  chest  the   pericardium,   the  left  carotid, 


Fig.  88. 

Pharynx    laid   open    from    behind:     1,    styloid    process;    2,    body   of 

;  Ital   bone;   :;,   septum   nasi;    1,   middle  turbinated  bone;   5,   posterior 

naris;   f,.    inferior  turbinated    bone;   7,   soft  palate;   !t,    uvula;    10,   tonsil; 

11,  bach  ol  tongue;  12,  epiglottis;  13,  arytenoepiglottidean  fold;  14    tip 

of  arytenoid  cartilage;   15,   esophagus;    16,    back  of  cricoid,  cartilage. 

lefl  subclavian,  the  aorta  ami  the  lefl  bronchus  are  in  front;  the  longua 

'"Hi    mUBCle    and    the    intercostal    vessels    and    the    vertebra]    column    are 

behind.  The  pleura  covers  it  laterally,  the  descending  portion  of  the 
arch  of  the  aorta  tying  on  the  left  ami  the  vena  azygos  major  on  the 
right. 

It-  structure  consists  of  three  coats: — 
Muscular  cat  (tunica  muscularis) ,  consisting  of  two  layers, 
the  longitudinal  and  the  circular,  continuous  with  the  inferior 
!  rictor: 


232 


HUMAN    ANATOMY. 


Areolar  or  fibrous  coat  (tela  submucosa),  connecting  the 
two; 

Mucous  coat  (tunica  mucosa),  covered  with  stratified  pave- 
ment epithelium,  and  having  beneath  it  some  non-striated  mus- 
cular fibers,  the  muscularis  mucosae.  It  also  contains  numerous 
compound  racemose  glands,  namely,  the  esophageal  glands. 


1,  left  hypochondriac  region;  2,  epigastric;  3,  right  hypochon- 
driac; 4,  left  lumbar;  5,  umbilical;  6,  right  lumbar;  7,  left  iliac; 
8,   hypogastric;    9,   right  iliac. 


THE    ABDOMEN. 

The  abdomen,  the  largest  cavity  in  the  body,  is  bounded 
in  front  and  laterally  by  the  abdominal  muscles,  the  lower  ribs, 
the  ilii,  above  by  the  diaphragm,  below  by  the  brim  of  the  pelvis, 
and  behind  by  the  vertebral  column,  quadratus  lumborum  and 
psoas  muscles.  It  is  lined  throughout  by  peritoneum,  inclosing 
the  greater  portion  of  the  alimentary  canal.  It  has  six  openings, 
as  follows: — 

Aortic  opening,  for  the  vena  azygos,  aorta  and  thoracic  duct; 
Esophageal  opening,  for  the  esophagus  and  pneumogastric  nerves; 
Quadrate  opening,  for  the  vena  cava  inferior; 


THE  ALIMENTARY  APPARATUS. 


233 


Umbilicus,  in  front,  for  the  fetal  umbilical  vessels; 
Femoral  canal    [vide  femoral  hernia); 

Inguinal  canal,  for  the  round  ligament  in  the  female,  and  the  sper- 
matic cord  in  the  male. 

Regions  of  the  Abdomen. — For  convenience  of  study,  the 
cavity  of  the  abdomen  is  divided  into  nine  regions  by  four 
imaginary  lines,  two  circular  lines  drawn  around  the  body,  one 
at  the  lower  margin  of  the  thorax  (Leidy)  or  on  a  level  with 
the  cartilages  of  the  ninth  rib,  the  second  at  the  highest  point 
of  the  crest  of  the  ilium;  and  two  vertical  lines,  drawn  from 
the  cartilage  of  the  eighth  rib  on  each  side  through  the  center 
of  Poupart's  ligament,  or  from  the  anterior  inferior  spinous 
process  of  the  ilium,  drawn  upward  (Leidy).  These  regions 
arc  named  as  follows: — 


Right    hypochondriac, 

Right  lumbar, 

Right  inguinal  (iliac), 


High  t  Hypochondriac. 
Hepatic  flexure  of 
colon,  right  lobe  of 
liver,  gall-bladder  and 
upper  part  of  right 
kidney. 


Right  Lumbar. 
Greater  part  of  right 
kidney,    ascending  co- 
lon   and     portions    of 

the    small    intestine. 


Right  Inguinal  (Iliac). 
Right  ureter,  cecum, 
•pelmatic   vessels  and 
appendix    ceci. 


Epigastric    region, 
Umbilical   region, 
Hypogastric    region, 

Contents   of  Regions. 

Umbilical. 
Left  lobe  of  liver, 
lobulus  Spigelii, 
greater  part  of  stom- 
ach, duodenum,  pan- 
creas, portions  of  the 
kidneys  and  supra- 
renal capsules,  vena 
cava,  aorta,  thoracic 
duct,  semilunar  gan- 
glia. 

Um  bilical. 
Transverse  portions 
of  colon  and  duode- 
num, jejunum,  and 
ileum,  part  of  mesen- 
tery and  great  omen- 
tum, receptaculum 
chyli  and  portions  of 
both    kidneys. 

Hypogastric. 

Portions  of  the  small 
intestine  under  cer- 
tain circumstances, 
the  uterus  ( preg- 
nant), bladder  (dis- 
tended), sometimes 
the      cecum,       sigmoid 

flexure  and  appendix. 


Left   hypochondriac, 

Left  lumbar, 

Left   inguinal    (iliac), 


Left  Hypochondriac. 
Splenic  flexure  of 
colon,  spleen,  tail  of 
pancreas,  splenic  end 
of  stomach  and  upper 
part  of   left  kidney. 


Left  Lumbar. 
Part  of  left  kidney, 
descending  colon,  some 
convolutions  of  small 
intestine  and  part  of 
the  omentum. 


Left  Inguinal   (Iliac). 
Left  ureter,  sigmoid 
flexure    "t'    colon    and 
spermatic  vessels. 


234  HUMAN    ANATOMY. 

Peritoneum  (tunica  serosa). — The  peritoneum  is  a  closed 
serous  sac,  its  parietal  layer  (perilotmum  parietale)  lining  the 
cavity  of  the  abdomen,  its  visceral  layer  (peritonceum  viscerale) 
inclosing  more  or  less  completely  all  the  abdominal  and  pelvic 
viscera.  It  is  not  in  all  cases  a  closed  sac,  for  in  the  female  it 
is  continuous  with  the  mucous  membrane  of  the  Fallopian  tubes. 
It  consists  essentially  of  two  sacs  of  unequal  size,  the  greater 
and  lesser  peritoneal  sacs,  united  by  a  central  constriction — the 
foramen  of  Winslow: — 

The  greater  sac  is  located  in  front  of  the  viscera,  one  layer 
lining  the  internal  abdominal  wall,  the  other  reflected  upon  the 
viscera.     Its  cavity  is  known  as  the  greater  peritoneal  cavity. 

The  lesser  sac  covers  the  upper  part  of  the  posterior  abdom- 
inal wall,  and  is  reflected  upon  the  posterior  surface  of  the  liver 
and  stomach.  Its  cavity  is  called  the  lesser  peritoneal  cavity. 
It  also  gives  off  three  processes,  one  of  which  is  a  broad,  loose 
fold, — the  great  omentum  (omentum  majus), — passing  down- 
ward from  the  greater  curvature  of  the  stomach  between  the 
two  layers  of  the  greater  sac,  and  is  reflected  upon  itself  back 
to  the  under  surface  of  the  transverse  colon. 

The  foramen  of  Winslow  (foramen  epiploicum  [Winsloivi]) 
is  a  narrow  canal,  large  enough  to  admit  one  finger,  between 
the  greater  and  ksser  peritoneal  cavities,  located  behind  the 
right  border  of  the  lesser  omentum,  and  formed  by  the  hepatic 
and  gastric  arteries,  constricting  the  sac  at  this  point  as  they 
ascend  from  the  celiac  axis.     It  is  bounded  as  follows : — 

In  front,  by  the  lesser  omentum,  containing  the  hepatic  artery, 
portal  vein,   duodenum  and  the   ductus   communis   choledochus; 

Behind,  by  the  right  crus  of  the  diaphragm  and  the  inferior  vena 
cava; 

Above,  by  the  lobus  Spigelii; 

Below,  by  the  hepatic  artery. 

Reflections. — The  reflections  of  the  peritoneum  viewed  in 
an  anteroposterior  section  (the  greater  and  lesser  sacs  together) 
may  be  traced  as  follows :  From  the  diaphragm  it  is  reflected  to 
the  upper  surface  of  the  liver.  Enveloping  this  organ  it  then 
presents  a  doubling  or  fold — the  gastrohepatic  omentum — ex- 
tending downward  from  the  transverse  hepatic  fissure  to  the 
lesser  curvature  of  the  stomach.  Inclosing  the  stomach,  it  is 
reflected  upon  itself  in  front  of  the  intestines  as  a  broad  apron 
■ — the  great  omentum  (omentum  majus) — making  a  quadruple 
fold  off  peritoneum. 

The  two  layers  then  embrace  the  transverse  colon,  unite 
and  pass  back  to  the  vertebral  column,  forming  the  transverse 


THE  ALIMENTARY  APPARATUS. 


235 


Fig.  90. 
The  abdominal   viscera.     {Schley.) 


236 


HUMAN    ANATOMY. 


mesocolon  (mesocolon  transversum) .  From  here  the  layers 
separate,  the  upper  one  ascending  in  front  of  the  pancreas  to 
the  starting  point.  The  lower  layer  descends  in  front  of  the 
duodenum,  incloses  the  small  intestine — forming  the  mes- 
entery proper — (mesenterium) ,  is  reflected  upon  the  rectum — 


Fig.  91. 

D,  diaphragm,;  L,  liver;  S,  stomach;  P,  pancreas;  D,  duodenum; 
C,  colon;  I,  small  intestine;  B,  bladder;  R,  rectum;  3,  posterior 
surface  of  liver;  4,  foramen  of  Winslow;  5,  great  omentum;  6, 
lesser  omentum;  7,  mesocolon;  8-9,  lesser  cavity  of  peritoneum;  10, 
mesentery;   11,  rectovesical  fold. 


forming  the  mesorecrum — and  upon  the  bladder,  and  ascends 
upon  the  anterior  abdominal  wall  to  the  starting  point. 

In  the  female,  from  the  rectum  it  envelops  the  uterus  and 
upper  part  of  the  vagina  before  reaching  the  bladder. 

In  addition  to  the  folds  seen  in  the  anteroposterior  section, 
the  peritoneum  passes  between  the  various  organs,  and  also  lat- 
erally to  the  sides  of  the  abdominal  and  pelvic  cavities.     In  this 


THE  ALIMENTARY  APPARATUS.  237 

manner  are  formed  the  right  lateral  (ligamentum  triangulare 
dextrum),  left  lateral  (ligamentum  triawgulare  sinistrum) ,  and 

suspensory  ligaments  of  the  liver  (ligamentum  falciforme  hep- 
atis),  the  suspensory  ligament  of  the  spleen  (ligamentum 
phrenicolienale) ,  the  broad  ligament  of  the  uterus  (ligamentum 
latum  uteri),  and  the  three  ligaments  or  omenta  of  the  stomach 
— the  gastrohepatic  (omentum  minus),  gastrosplenic  (ligamen- 
tum gastrolienale) ,  and  gastrocolic  (omentum  majus)  (already 
described)  and  the  mesenteries. 

The  latter,  the  mesenteries,  include  the  mesentery  proper, 
mesocecum ;  ascending  (mesocolon  ascendens) ,  transverse  (meso- 
colon transversum ) .  and  descending  mesocolon  (mesocolon 
descendens),  sigmoid  mesocolon  (mesocolon  sigmoideum)  and, 
mesorectum. 

The  mesentery  proper  (mesenterium)  is  a  broad  fold,  re- 
flected from  the  vertebras  around  the  jejunum  and  ileum.  Its 
base,  attached  obliquely  from  the  left  side  of  the  second  lumbar 
vertebra  to  the  right  iliac  region,  measures  about  six  inches, 
while  its  expanded  extremity  is  quite  considerable. 

In  the  male  the  rectovesical  folds,  one  on  each  side,  pass 
from  the  rectum  to  the  bladder,  including  between  them  the 
rectovesical  pouch  (excavatio  rectovesical) .  In  the  female, 
however,  this  pouch  is  divided  into  two — the  rectouterine  and 
vesicouterine  pouches  (excavatio  vesicoaterina),  the  rectovesical 
folds  being  called  rectouterine  and  vesicouterine  folds  (plica 
rectouterine^) .  Folds  of  peritoneum  (superior  false  ligaments 
of  the  bladder)  (plicce  umbilicalis  media)  ascend  from  the  blad- 
der to  the  umbilicus,  inclosing  the  remains  of  the  fetal  urachus 
(ligamentum  umbilicale  medium)  and  hypogastric  arteries,  and 
also  a  fold  on  each  side  follows  the  course  of  the  epigastric 
arteries  toward  the  umbilicus,  dividing  the  inguinal  region  into 
the  internal,  middle  and  external  inguinal  fossa?.  The  peri- 
toneum at  the  external  inguinal  fossa  (corresponding  to  the 
internal  abdominal  ring)  is  continuous  in  the  male  fetus  with 
the  tunica  vaginalis  testis,  and  in  the  female  forms  a  blind  sac 
about  the  round  ligament — the  canal  of  Nuck. 

Viscera  Partly  Invested  by  Peritoneum. 

Vagina     upper  part; 

Bladder     posterior   wall; 

Duodenum — descending  and  transverse  portions; 

Cecum : 

Colon     ascending  and  descending; 

Bed  inn — middle  porl  ion. 


238  HUMAN    ANATOMY. 


Viscera  Entirely  or  Almost  Entirely  Covered. 

Stomach,  Sigmoid  flexure, 

Spleen,  Rectum — upper  part, 

Ileum,  Liver, 

Jejunum,  Uterus, 

Colon — transverse  Ovaries. 


Viscera  Without  Peritoneal  Investment 

Bladder — except  posterior  wall; 

Rectum- — lower  third; 

Vagina — lower  part  of  posterior  wall; 

Pancreas, 

Suprarenal  capsules,     J-  partly  covered  anteriorly. 

Kidneys, 


THE   STOMACH. 

The  stomach  (ventriculus)  is  a  musculomembranons  sac, 
pyriform  in  shape,  situated  below  the  diaphragm  in  an  oblique 
position  across  the  upper  abdomen,  where  it  is  held  in  position 
by  the  lesser  omentum  and  the  gastrosplenic  ligament.  It 
measures  about  nine  to  twelve  inches  in  length,  four  to  five 
inches  in  its  greatest  diameter,  and  has  a  capacity  of  from  one 
to  two  quarts.  It  occupies  the  epigastric,  right  and  left  hypo- 
chondriac regions,  and  is  in  relation  above  with  the  diaphragm 
and  liver,  below  with  the  transverse  colon,  in  front  with  the  ab- 
dominal walls,  and  behind  with  the  pancreas.  When  distended 
the  stomach  rotates  on  its  long  axis  and  the  greater  curvature 
points  somewhat  forward.  It  presents  for  examination  a  greater 
and  lesser  extremity,  greater  and  lesser  curvatures,  anterior  and 
posterior  surfaces,  and  cardiac  and  pyloric  orifices. 

The  greater  extremity,  or  fundus  (fundus  ventriculi),  oc- 
cupies the  left  hypochondriac  region,  in  contact  with  the  spleen, 
with  which  it  is  attached  by  the  gastrosplenic  omentum,  and 
behind  the  lower  rib. 

The  lesser  or  pyloric  end  is  smaller  and  lies  in  contact  with 
the  under  surface  of  the  liver  and  the  wall  of  the  abdomen  in 
the  right  hypogastric  region. 

The  greater  curvature  (curvaturd  ventriculi  major)  extends 
between  the  pyloric  and  esophageal  orifices,  along  the  lower 
border  of  the  stomach,  and  to  it  is  attached  the  great  omentum. 

The  lesser  curvature  (curvatura  ventriculi  minor)  extends 
between  the  same  two  points  along  the  superior  border  of  the 
organ. 


THE  ALIMENTARY  APPARATUS.  339 

The  esophageal  or  cardiac  orifice  occupies  the  highest  part 
of  the  stomach,  behind  the  seventh  left  costal  cartilage,  and 
receives  the  esophagus. 

The  pyloric  orifice  occupies  the  right  extremity,  and  opens 
into  the  duodenum,  being  protected  by  a  muscular  valve,  the 
pylorus,  or  pyloric  valve  (valvula  pylori). 

The  anterior,  upper  or  parietal  surface  (paries  anterior)  is 
in  contact  with  the  under  surface  of  the  left  lobe  of  the  liver, 
the  abdominal  walls  and  the  diaphragm. 

The  posterior,  lower  or  visceral  surface  (paries  posterior) 
is  in  contact  with  the  peritoneum  of  the  diaphragm,  solar 
plexus,  the  pancreas  and  the  abdominal  vessels. 

The  structure  of  the  stomach  consists  of  four  coats,  a  se- 
rous, muscular,  fibrous  or  areolar  and  mucous. 

The  serous  coat  (tunica  serosa)  is  derived  from  the  peri- 
toneum, which  completely  covers  it,  except  along  the  lesser  and 
greater  curvatures,  where  the  vessels  and  nerves  enter. 

The  muscular  coat  (tunica  muscularis)  consists  of  three 
sets  of  fibers :— - 

The  longitudinal  (stratum  longitudinale) ,  the  most  super- 
ficial, are  continuous  with  the  longitudinal  fibers  of  the  small 
intestine  below,  and  the  esophagus  above; 

The  circular  fibers  (stratum  circulare),  the  second  layer, 
are  most  abundant  at  the  pyloric  extremity,  where  they  form 
the  pyloric  valve  (valvula  pylori). 

The  oblique  fibers  (fibres  obliques)  are  distributed  over  both 
surfaces,  passing  obliquely  from  right  to  left  and  left  to  right. 

The  areolar  or  submucous  coat  (tela  submucosa)  connects 
the  muscular  with  the  mucous  layer,  and  is  sometimes  named 
the  vascular  coat. 

The  mucous  membrane  (tunica  mucosa)  is  of  a  pale  pink- 
ish-ash  color,  thickened  toward  the  pylorus,  where  it  presents 
numerous  rugae,  or  pleats  (plica  mucosal),  and  at  the  pyloric 
end  it  helps  to  form  the  pyloric  valve.  It  is  lined  throughout 
with  columnar  epithelium,  and  is  studded  with  three  kinds  of 
minute  tubes,  the  gastric  follicles  and  lenticular  glands.  The 
gastric  follicles  consist  of  two  kinds,  the  pyloric  (glandulcB 
pyloricce)  and  the  peptic  glands  (glandular  gastricoB  propria), 
the  former  most  abundant  at  the  pyloric  end  and  the  latter 
distributed  all  over  the  surface  of  the  Btomach. 

The  pyloric  or  mucous  glands  (glandvlm  pyloricce)  each 
consisl  of  from  two  to  lour  blind  tubes  opening  into  a  common 
duct,  and  lined  throughout  by  columnar  epithelium. 


240  HUMAN    ANATOMY. 

The  peptic  glands  {glandular  gstricce  proprice)  are  similar 
in  structure,  but  have  a  much  shorter  duct,  and  contain  in  addi- 
tion peculiar  large,  spheroidal,  granular  peptic  cells. 

The  lenticular  or  simple  solitary  glands  {nocluli  lymphatici 
solitarii)  are  small  masses  of  lymphoid  tissue  scattered  through- 
out the  connective-tissue  framework  of  the  stomach  between  the 
gastric  follicles. 

The  arteries  are  derived  from  the  gastric,  pyloric,  right 
gastroepiploic  branches  of  the  hepatic  artery,  and  the  left  gas- 
troepiploic and  vasa  brevia  branches  of  the  splenic  artery  {vide 
Arterial  System). 

The  veins  terminate  in  the  portal,  superior  mesenteric  and 
splenic  veins. 

The  nerves  are  derived  from  the  gastric  plexuses  (A.uer- 
bach's  and  Meissner's  plexuses,  in  the  muscular  and  submucous 
coats,  respectively),  formed  by  the  terminal  branches  of  the 
right  and  left  pneumogastric,  and  the  branches  of  the  celiac 
plexus,  an  offshoot  of  the  solar  plexus  of  the  sympathetic. 

THE   SMALL   INTESTINE    (iNTESTINUM    TENUE). 

The  small  intestine  is  a  convoluted  tube  about  twenty  to 
twenty-five  feet  in  length,  for  the  chylification  of  the  food, 
occupying  the  lower  and  central  portions  -of  the  abdominal  and 
pelvic  cavities,  and  held  in  position  to  the  spinal  column  by  the 
mesentery.  It  is  divided  into  three  portions — the  duodenum, 
jejunum  and  ileum. 

The  duodenum,  so  called  from  being  in  length  about 
twelve  fingers'  breadth,  is  about  eight  to  ten  inches  long.  It 
consists  of  four  portions,  from  the  position  of  its  course — 
ascending,  descending,  transverse  and  terminal  ascending: — 

The  first,  ascending  or  superior  portion  {pars  superior)  is 
about  two  inches  in  length,  and  ascends  to  the  neck  of  the  gall- 
bladder. It  is  completely  invested  by  peritoneum  for  about  an 
inch. 

The  second  or  descending  portion  {pars  descendens) ,  about 
three  inches  in  length,  descends  in  front  of  the  right  kidney  as 
far  as  the  third  or  fourth  lumbar  vertebra,  and  is  overlapped 
in  front  by  the  head  of  the  pancreas,  and  into  its  posterior 
aspect,  the  duct  of  the  pancreas  and  the  common  biliary  duct 
open  by  a  common  orifice. 

The  third,' preaortic,  horizontal  or  transverse  portion  is 
attached  to  the  crura  of  the  diaphragm  and  the  vessels  in  front 
of  the  vertebral  column,  passes  behind  the  transverse  mesocolon, 


THE  ALIMENTARY  APPARATUS.  341 

and  has  the  pancreas  above  it,  while  the  superior  mesenteric 
blood  vessels  cross  from  beneath  the  latter  between  the  two,  or 
over  the  duodenum. 

The  fourth  or  terminal  ascending  portion  (pars  ascendens) 
runs  upward  and  forward  to  the  duodenojejunal  flexure. 

The  arteries  are  derived  from  the  inferior  pancreatico- 
duodenal branch  of  the  superior  mesenteric  and  the  superior 
pancreaticoduodenal  branch  of  the  gastroduodenal,  a  branch  of 
the  hepatic.  The  veins  terminate  in  the  superior  mesenteric 
and  splenic  veins.    The  nerves  are  from  the  solar  plexus. 

The  jejunum  (intestinum  jejunum),  named  from  jejunus^ 
empty,  includes  the  upper  two-fifths  of  the  small  intestine,  is 
continuous  above  with  the  duodenum  and  below  with  the  ileum. 
It  occupies  chiefly  the  left  iliac  and  umbilical  region. 

The  ilki'.m  (intestinum  ileum),  so  called  from  its  twisted 
appearance,  includes  the  remaining  three-fifths,  is  continuous 
above  with  the  jejunum  and  below  with  the  caput  cecum  of  the 
large  intestine.  It  occupies  the  right  iliac,  hypogastric  and 
umbilical  regions. 

The  structure  of  the  small  intestine  consists  of  four  coats — 
the  serous,  muscular,  fibrous  or  areolar  and  mucous : — 

The  serous  coat  (tunica. serosa)  is  the  peritoneal  covering; 

The  muscular  coat  (tunica  muscularis)  consists  of  two  sets 
— a  Longitudinal  and  a  circular; 

The  areolar  or  submucous  coat  (tela  submucosa)  connects 
the  muscular  with  the  mucous  coat; 

The  mucous  coat  (tunica  mucosa)  is  thinner  and  redder 
than  that  of  the  stomach,  and  is  thrown  into  numerous  trans- 
verse folds — the  valvulae  conniventes — most  numerous  in  the 
upper  part;  they  diminish  as  it  descends  and  finally  disappear 
in  the  ileum.  They  increase  the  secreting  and  absorbing  surface 
of  the  mucous  membrane  and  retard  the  passage  of  the  food. 

The  mucous  membrane  also  contains  the  villi  and  four 
kinds  of  glands: — 

Simple   follicles,  or  crypts  of  Lieberkiihn; 
Duodenal  glands,  or  Brunner's  glands; 
Solitary  glands; 
Agminate,  or  Fever's  glands. 

The  villi  (villi  iulcsliiinles)  are  minute  vascular  projec- 
tion- of  the  mucous  membrane  scattered  throughout  the  surface 
of  the  small  intestine.  Their  structure  consists  of  a  pouch-like 
termination  of  a  lacteal  in  the  center,  surrounded  by  a  minute 
plexus  of  capillary  vessels,  inclosed  in  a  basement  membrane  ami 
covered  with  columnar  epithelium. 

ie 


24:2  HUMAN    ANATOMY. 

The  simple  follicles,  or  crypts  of  Lieberkiihn  (glandules 
intestinales  [Lieberkiihnt]) ,  are  scattered  throughout  the  mu- 
cous membrane  of  the  entire  small  intestine.  They  consist  of 
minute  tubes  of  basement  membrane,  lined  with  columnar  epi- 
thelium and  surrounded  by  a  capillary  network. 

The  duodenal  or  Brunner's  glands  (glandulce  duodenales 
[Brunneri] )  are  distributed  to  the  doudenum  and  jejunum 
only.  They  are  largest  and  most  numerous  in  the  vicinity  of 
the  pylorus.  They  are  composed  of  tubular  alveoli,  lined  by 
epithelium,  and  having  a  small  duct  opening  on  the  mucous 
membrane. 

The  solitary  glands  (noduli  lymphatici  solitarii)  are  dis- 
tributed throughout  the  small  intestine,  being  most  numerous 
in  the  last  portion  of  the  ileum.  They  consist  of  lymph  folli- 
cles, and  communicate  with  the  lacteal  system  by  means  of 
lymph  spaces. 

Peyer^s  glands,  or  Peyer's  patches  (noduli  lymphatici  ag- 
gregati  [Peyeri] ) ,  consist  of  an  aggregation  of  the  solitary 
glands  into  oval  groups  of  twenty  or  thirty,  along  the  small 
intestine  at  a  point  opposite  the  attachment  of  the  mesentery. 
The  patches  are  about  fifteen  to  thirty  in  number,  each  meas- 
uring about  one-half  to  two  inches  in  length  and  one-half  inch 
in  breadth.  Their  axes  are  parallel  with  the  length  of  the 
intestine.  In  the  duodenum  they  are  few  and  small  in  size,  and 
the  mucous  membrane  of  the  valvulse  conniventes  over  them  is 
reduced  in  size  and  much  distorted. 

The  arteries  are  derived  from  the  pyloric,  pancreatico- 
duodenal and  superior  mesenteric.  They  reach  the  intestines 
inclosed  in  and  along  the  course  of  the  mesenteries.  In  the 
intervals  of  the  coats  they  form  three  vascular  nets,  which  sup- 
ply the  serous,  muscular  and  mucous  coats.  The  veins  accom- 
pany the  arteries  and  join  the  portal  vein. 

The  lymphatics  follow  the  course  of  the  superior  mesenteric 
vessels  to  enter  the  mesenteric  glands. 

The  nerves  are  derived  from  the  solar  plexus  of  the  sym- 
pathetic. 

THE    LARGE    INTESTINE    (iNTESTINUM    CRASSUM). 

The  large  intestine  is  about  five  feet  long  and  extends  from 
the  ileum  to  the  anus. 

It  commences  in  the  right  iliac  fossa,  ascends  through  the 
right  lumbar  and  right  hypochondriac  regions,  passes  trans- 
versely between  the  epigastric  and  umbilical  regions  to  the  left 


THE    ALIMENTARY    APPARATUS.  243 

hypochondriac  region,  where  it  descends  through  the  left  hypo- 
chondriac, lumbar  and  iliac  regions,  and  through  the  pelvis  on 
its  posterior  wall  to  terminate  at  the  anus. 
It  consists  of  three  divisions: — 

1.  Cecum. 

f  Ascending, 
9    pi  j  Transverse, 


Descending, 
[  Sigmoid  flexure. 


3.  Rectum. 


The  cecum  (in-testinum  cn'cum)  is  a  blind  pouch  measur- 
ing about  two  and  one-half  inches  in  every  diameter,  lying  free 
in  the  right  iliac  region. 

It  has  opening  into  its  lower  back  part  the  appendix  vermi- 
formis,  and  into  its  inner  back  part  the  ileum,  guarded  by  the 
ileocecal  valve. 

The  appendix  vermiformis  {processus  verm-iformifi)  is  a 
long,  narrow,  twisted  tube,  the  rudiment  of  the  prolonged  cecum 
in  all  mammalia.  It  terminates  in  a  blunt  extremity.  Its 
mucous  membrane  is  continuous  with  that  of  the  cecum,  and 
contains  many  solitary  glands. 

The  ileocecal  valve  (vulvula  coli),  or  valve  of  Bauhin,  pro- 
tects the  opening  of  the  ileum  into  the  cecum,  and  consists  of 
two  valve-like  semilunar  folds  of  mucous  membrane,  strength- 
ened by  bands  of  circular  fibers.  The  upper  one  is  attached  to 
the  junction  of  the  ileum  with  the  colon,  the  lower  one  to  the 
junction  of  the  ileum  with  the  cecum.  On  each  side  where  the 
folds  coalesce,  a  ridge  of  mucous  membrane,  continuous  for  a 
short  distance  around  the  canal,  forms,  the  frenulum  or  retinac- 
ulum (frrniini  valvules  coli)  of  the  valve.  The  mucous  mem- 
brane on  either  side  of  the  valves  corresponds  to  that  of  the 
large  and  small  intestines  respectively,  being  covered  with  villi 
on  the  side  toward  the  ileum,  and  being  destitute  of  villi,  and 
containing  numerous  tubular  glands  or  crypts  of  Lieberkiibn,  on 
the  Bide  toward  the  cecum.  This  difference  occurs  abruptly  at 
the  free  margin  of  the  valves. 

The  COLON  consists  of  four  portions — ascending,  trans- 
verse, and  descending  colon  and  sigmoid  flexure: — 

The  ascending  portion  (colon  ascendens)  begins  opposite 
the  ileocecal  valve,  ascends  through  the  right  lumbar  and  hypo- 
chondriac regions,  and  terminates  beneath  the  under  Burface  of 
the  liver  at  the  hepatic  flexure  (flexura  coli  dextra)  in  the 
transverse    portion.      Its    posterior   surface    is   destitute   of   peri- 


244  HUMAN    ANATOMY. 

toneum,  and  is  attached  to  the  quadratus  luniborum  muscle  by 
loose  areolar  tissue. 

The  transverse  portion,  or  transverse  arch  of  the  colon 
(colon  transversum) ,  passes  from  the  hepatic  flexure,  through 
the  adjoining  portions  of  the  epigastric  and  umbilical  regions, 
to  terminate  at  the  splenic  flexure  (flexura  coli  sinistra)  in  the 
descending  portion.  It  is  attached  by  transverse  mesocolon,  and 
is  the  most  movable  portion  of  the  colon. 

The  descending  portion  (colon  descendens)  begins  at  the 
splenic  flexure,  descends  through  the  left  lumbar  and  iliac 
regions  to  terminate  in  the  sigmoid  flexure.  Like  the  ascending 
colon,  its  posterior  surface  is  destitute  of  peritoneum. 

The  sigmoid  flexure — omega  loop — (colon  sigmoideum)  is 
a  narrow,  twisted  portion  of  the  colon,  occupying  the  left  iliac 
fossa,  between  the  descending  portion  of  the  colon  and  'the  rec- 
tum. It  is  held  in  position  by  the  sigmoid  mesocolon.  It 
terminates  opposite  the  third  sacral  vertebra. 

The  rectum  (intestinum  rectum) — the  terminal  portion 
— extends  from  the  sigmoid  flexure  to  the  anus.  It  is  four  to 
six  inches  in  length,  not  sacculated,  but  club-shaped,  with  its 
large  extremity  downward,  and  consists  of  two  portions — supe- 
rior and  inferior: — 

The  lower  four  inches,  formerly  described  as  the  upper  por- 
tion of  the  rectum,  rest  upon  the  sacral  plexus  of  nerves  and 
the  pyriformis  muscle; 

The  superior  portion,  about  three  and  three-quarters  inches, 
is  in  relation  in  the  male  with  the  bladder,  prostate  gland  and 
vesiculse  seminalis;  in  the  female  with  the  uterus  and  vagina, 
being  adherent  to  the  latter ; 

The  inferior  portion,  about  one  and  one-quarter  inches, 
turns  backward  and  terminates  in  the  anus.  It  is  supported  by 
the  levator  ani  muscle,  and  is  surrounded  by  the  internal  and 
external  sphincters  of  the  anus.  The  structure  of  the  large 
intestine  consists  of  four  coats — serous,  muscular,  cellular  and 
mucous : — 

The  serous  coat  (tunica  serosa),  derived  from  the  perito- 
neum, invests  completely  the  transverse  and  sigmoid  portions  of 
the  colon,  but  only  partially  the  others,  being  absent  in  the  pos- 
terior surfaces  of  the  ascending  and  descending  portions,  and 
on  the  superior  part  of  the  rectum.  The  inferior  surface  of  the 
rectum  is  without  peritoneal  covering.  The  appendices  epi- 
ploicce  are  folds  of  serous  membrane  filled  with  fat  and  attached 
chiefly  to  the  transverse  colon. 


THE  ALIMENTARY  APPARATUS.  245 

The  muscular  coat  (tunica  muscularis)  consists  of  longi- 
tudinal fibers  arranged  into  three  flat  bands,  shorter  by  nearly 

one-half  than  the  intestine  itself,  and  the  circular,  distributed 
more  evenly,  but  accumulated  at  points,  producing  with  the 
former  a  sacculated  condition. 

The  cellular  coat  connects  the  mucous  with  the  muscular 
coat  beneath. 

The  mucous  coat  (tunica  mucosa)  is  smooth,  destitute  01 
villi  and  valvulae  conniventes,  and  thrown  into  numerous  folds, 
two  to  four  of  which,  situated  in  the  rectum,  have_  received  the 
name  of  Houston's  valves  (plica?  transversal es  recti). 

It  contains  crypts  of  Lieberkulm,  more  numerous  here  than 
in  the  small  intestine,  and  solitary  glands  scattered  throughout, 
but  most  numerous  in  the  appendix  and  cecum,  where  some  of 
them  are  accumulated  into  Peyer's  patches. 

The  arteries  of  the  cecum  and  colon  are  from  the  mesen- 
teric. The  lymphatics  empty  into  the  mesenteric  glands,  and 
the  nerves  are  derived  from  the  mesenteric  plexus  of  the  sym- 
pathetic system. 

The  arteries  of  the  rectum  are  the  hemorrhoidal  branches 
of  the  inferior  mesenteric,  internal  iliac  and  internal  pudic. 
The  veins  form  the  hemorrhoidal  plexus,  and  empty  into  the 
inferior  mesenteric  and  internal  iliac  veins. 

The  lymphatics  go  to  the  sacral  and  lumbar  glands,  and  the 
nerves  are  from  the  hypogastric  plexus  of  sympathetic  and  con- 
tiguous spinal  nerves. 

THE    PANCREAS. 

The  pancreas  is  an  oblong,  compound,  racemose  gland, 
about  six  to  eight  inches  in  length,  one  and  one-half  inches  in 
breadth,  and  one-half  to  one  inch  in  thickness,  situated  across 
the  back  part  of  the  epigastric  and  left  hypochondriac  regions. 
In  weight  varies  from  two  to  six  ounces. 

It  consists  of  a  head,  body  and  tail : — 

The  head  (caput  pancreatic),  or  right  extremity,  is  received 
int.,  the  concavity  of  the  duodenum.  The  'lesser  pancreas,  a 
detached  portion  of  the  gland,  lies  behind  it. 

The  tail,  or  lesser  nnl,  terminates  above  the  left  kidney 
and   suprarenal   capsule,   in   contact    with   the  spleen. 

The  body  (corpus  paw-real  is)  is  in  relation  in  front  with 
the  stomach  ami  transverse  mesocolon;  behind  it  rests  upon  the 
first  lumbar  rertebra,  having  interposed  the  crura  of  (he  dia- 
phragm, \ena  cava,  left  renal   win,  aorta,  superior  mesenteric 


2^6  HUMAN    ANATOMY. 

artery  and  vein,  the  inferior  mesenteric  vein  and  commence- 
ment of  portal  vein. 

The  splenic  artery  and  vein  are  lodged  in  a  groove  on  its 
upper  border. 

The  pancreatic  duct,  or  canal  of  Wirsung  (ductus  pan- 
creations  [Wirsungi~\) ,  runs  throughout  the  substance  of  the 
organ,  to  emerge  at  the  head,  and  open  into  the  duodenum  by 
an  orifice  in  common  with  the  ductus  communis  choledochus. 
The  lesser  pancreas,  when  it  exists,  empties  by  the  ductus  pan- 
creaticus  minor. 

The  structure  resembles  that  of  the  salivary  glands,  but  is 
softer  and  looser. 

Arteries  are  from  the  splenic  and  pancreaticoduodenal 
branches  of  the  hepatic  and  superior  mesenteric. 

The  veins  join  the  splenic  or  superior  mesenteric. 

The  nerves  are  from  splenic  plexus  of  the  sympathetic. 

The  lymphatics  empty  into  the  lumbar  glands. 

THE    LIVER    (HEPAR). 

The  liver  is  the  largest  gland  in  the  body,  measuring  in 
its  transverse  diameter  from  ten  to  twelve  inches,  and  its  antero- 
posterior six  to  seven,  and  its  thickest  part  about  three  inches, 
and  weighing  about  from  three  to  four  pounds.  It  occupies 
the  upper  part  of  the  abdominal  cavity,  and  the  right  hypo- 
chondriac, epigastric,  and  a  portion  of  the  left  hypochondriac 
regions.  Its  upper  surface  is  convex  and  rests  against  the  dia- 
phragm and  a  small  portion  of  the  abdominal  parietes  in  front. 
Its  lower,  or  visceral  surface  (fades  inferior),  is  in  contact  with 
the  duodenum  and  stomach,  the  right  kidney  and  suprarenal  cap- 
sules, and  the  hepatic  flexure  of  the  colon.  It  is  divided  by  the 
longitudinal  fissure  into  the  right  and  left  lobes  (lobuli  hepatis) . 
The  liver  has  five  fissures,  five  lobes,  five  ligaments,  five  sets  of 
vessels,  and  is  inclosed  in  a  fibrous  coat,  continuous  at  the  trans- 
verse fissure  with  the  capsule  of  Glisson.  It  is  also  invested  by 
the  peritoneum,  except  at  the  attachment  of  the  coronary  liga- 
ment. 

Structure. — The  liver  is  made  up  of  lobules,  which  are 
small,  granular  bodies  about  one-fifteenth  of  an  inch  in  diam- 
eter, held  together  by  delicate  connective  tissue  and  the  branches 
of  the  five  sets  of  vessels  (to  be  described)  and  nerves,  the  whole 
being  inclosed  in  a  serous  and  fibrous  coat. 

Each  lobule  is  made  up  of  a  mass  of  polyhedral,  nucleated 
fells,  inclosed  in  a  capillary  plexus   derived  from  the  hepatic 


\ 


THE  ALIMENTARY  APPARATUS. 


;m; 


artery  and  portal  vein,  and  giving  origin  to  the  hepatic  vein 
and  biliary  duct. 

The  five  fissures  of  the  liver  are  all  situated  on  its  under 
surface.  They  separate  the  five  lobes  from  one  another.  They 
are  : — 

1.  Longitudinal  fissure  (fossa  longitudinalis  sinistra)  ex- 
tends from  before  backward,  from  the  notch  in  front  to  the 
posterior  border.  It  is  sometimes  called  the  umbilical  fissure 
(fossa  vencB  umbilicalis) ,  and  lodges  the  round  ligament,  the 
remains  of  the  fetal  umbilical  vein. 

2.  Fissure  for  the  ductus  venosus  (fossa  ductus  venosi)  is 


u 


^#\ 


x_ 


Fig.  92 

1,  left  lobe;  2,  right  lobe;  3,  quadrate  lobe;  4,  caudate _lflhg;  5, 
Spigelian  lobe;  6,  hepatic  artery;  7,  portal  vein;  8,  Assure  of  ductus 
venosus;  9,  gall-bladder;  10,  cystic  duct;  11,  hepatic  duct;  12,  fissure 
for  vena  cava;  13,  vena  cava;  14,  right  inferior  phrenic  vein;  15, 
hepatic  vein;   16,   right  renal  vein;   17,   left  renal  vein. 

the  posterior  portion  of  the  longitudinal  fissure,  and  lodges  the 
remains  of  the  ductus  venosus  of  fetal  life. 

:;.  Transverse    fissure,    or   portal    fissure    (porta    hepatic), 
-  the  inferior  surface  of  the  liver  transversely  ami  joins 
the  Longitudinal.     It  transmits  the  portal   vein,  hepatic  artery 
and  nerves,  and  the  hepatic  duct  and  lymphatics. 

I.  Fissure  for  the  gall-bladder  (fossa  vesica-  frllea?)  is  ? 
shallow  depression  beneath  the  right  lobe,  running  parallel  wit' 
the  longitudinal  fissure  in  front. 

Fissure  for  the  vena  cava  (fossa  venm  cava?)  runs  obliq1    ly 
upward  along  the  inferior  surface  oear  its  posterior  marg      to 


248  HUMAN    ANATOMY. 

the  left  side,  joining  the  fissure  for  the  ductus  venosus  behind, 
and  separated  from  the  transverse  fissure  in  front  by  the  lobulus 
caudatus.  It  lodges  the  inferior  cava,  which,  within  this  fissure, 
receives  the  hepatic  veins. 

The  five  lobes  of  the  liver  are : — 

Eight  lobe  {lotus  liepatis  dexter),  much  the  largest,  is 
somewhat  quadrilateral  in  outline,  and  presents  three  fissures 
and  two  depressions,  the  latter  one  for  the  right  kidney  and  its 
suprarenal  capsule,  and  the  other  for  the  hepatic  flexure  of  the 
colon. 

Left   lobe    (lobus   liepatis   sinister),   smaller,   is   separated 


Fig.  93. 

Transverse   section    of    lobules   of   liver:     (a),    interlobular  vein;    (&), 
intralobular   central   vein. 

from  the  right  lobe  by  the  longitudinal  fissure,  and  is  in  con- 
tact with  the  stomach. 

Lobulus  quadratus,  or  square  lobe,  occupies  the  anterior 
border  of  the  under  surface  of  the  right  lobe,  between  the  um- 
bilical fissure  and  the  fissure  for  the  gall-bladder,  and  in  front 
of  the  transverse  fissure. 

Lobulus  Spigelii  {lobus  caudatus  [Spigeli])  occupies  a 
similar  position  to  the  quadrate  lobe,  along  the  posterior  bor- 
der, immediately  back  of  it,  from  which  it  is  separated  by  the 
transverse  fissure.  It  is  bounded  laterally  by  the  fissures  for 
the  ductus  venosus  and  vena  cava. 

Lobulus  caudatus,  or  tailed  lobe,  unites  the  lobus  Spigelii 
with  the  right  lobe,  and  separates  the  transverse  fissure  from 
the  fit  nre  for  the  vena  cava. 


THE    ALIMENTARY    APPARATUS.  249 

The  five  ligaments  of  the  liver  are  folds  of  peritoneum 
except  one,  the  "round  ligament,  which  is  the  remains  of  the 
umbilical  vein  and  ductus  venosus  of  the  fetus. 

They  are: — 

1.  Longitudinal  or  falciform  ligament  (ligamentum  fahir 
forme  hepatis)  consists  of  two  layers  of  peritoneum,  attached 
by  one  margin  to  the  under  surface  of  the  diaphragm,  and  the 
sheath  of  the  right  rectus  muscle,  and  is  attached  to  the  liver 
along  its  anterior  margin,  from  the  notch  to  its  posterior  border. 

2  and  3.  The  lateral  ligaments  (ligamenta  triangulare  dex- 
trum  ct  sinistrum) ,  one  on  either  side,  are  triangular  layers  of 
peritoneum,  attached  to  the  lateral  edges  of  the  liver  toward 
its  posterior  margin. 

4.  The  coronary  ligament  (ligamentum  coronarium  hep- 
atis) is  formed  of  two  layers,  continuous  with  the  lateral  liga- 
ment and  with  the  longitudinal  ligament,  connecting  the  pos- 
terior border  of  the  liver  to  the  diaphragm. 

5.  The  round  ligament  (ligamentum  teres  hepatis)  is  a 
fibrous  cord,  the  remains  of  the  obliterated  umbilical  vein  and 
ductus  venosus,  extending  from  the  umbilicus  to  the  longi- 
tudinal fissure,  extending  as  far  back  as  the  inferior  vena  cava. 

The  five  sets  of  vessels  are  the  hepatic  artery,  portal  vein, 
hepatic  veins,  hepatic  ducts  and  lymphatics: — 

The  hepatic  artery,  the  nutrient  vessel  of  the  liver,  one  of 
the  branches  of  the  celiac  axis,  enters  the  transverse  fissure,  and 
after  giving  off  branches  to  the  capsule  of  Grlisson  (capsula 
fibrosa  [Glissoni]),  and  to  the  capsule,  divides  into  interlobular 
branches,  which  form  plexuses  around  each  lobule,  and  ter- 
minate in  capillaries  between  the  cells,  anastomosing  with  the 
capillaries  of  the  portal  vein. 

The  portal  rein  enters  at  the  transverse  fissure,  divides  into 
two  branches,  and  finally  terminates  in  the  interlobular  plexuses, 
already  described.  These  all  unite  into  one  vein — intralobular 
vein — -traversing  the  center  of  the  lobule  to  join  the  sublobular 
nil,,  the  latter  ending  in  the  hepatic  veins.  These  latter  finally 
terminate  in  the  inferior  vena  cava. 

The  hepatic  ducta  (ductus  ln'/iaticus)  originate  between  the 
hepatic  cells  as  bile  capillaries,  minute  canals  without  walls,  and 
form  a  plexus  between  the  lobules.  From  these  plexuses  ductf 
eonverge  and  unite  to  finally  form  the  hepatic  duct. 

The  lymphatic  vessels  form  two  sefs — the  superficial,  th  e 
upon  the  surface  of  the  organ;  and  deep,  those  accompaspv ug 
the  branches  of  the  bepatic  arteries  and  portal  vein. 


250  HUMAN    ANATOMY. 

The  gall-bladder  (vesica  fellea)  is  a  conical  membranous 
sac  attached  to  the  under  surface  of  the  right  lobe  of  the  liver, 
and  partly  covered  by  peritoneum.  It  measures  about  four 
inches  by  one,  and  has  a  capacity  of  about  nine  drachms.  It 
consists  of  a  fundus  (fundus  vesicce  fellece),  or  rounded  extrem- 
ity, a  body  (corpus  vesicce  fellece)  and  neck  (collum  vesicce 
fellece),  and  has  three  coats — a  fibrous,  muscular  and  mucous — 
the  latter  lined  with  columnar  epithelium. 

The  neck  terminates  in  the  cystic  duct,  the  mucous  mem- 
brane of  which  is  thrown  into  a  series  of  folds,  forming  a  spiral 
valve. 

The  ductus  communis  choledochus  (ductus  choledochus) , 
or  common  biliary  duct,  about  three  inches  long  and  the  diam- 
eter of  a  goose-quill,  is  formed  by  the  union  of  the  hepatic, 
about  two  inches  in  length,  and  the  cystic  (ductus  cysticus), 
about  one  inch  in  length.  It  empties  into  the  descending  por- 
tion of  the  duodenum  in  common  with  the  pancreatic  duct, 
about  three  and  one-half  inches  below  the  pylorus. 

THE    DUCTLESS    GLANDS. 

The  following  group  includes  the  glands  without  ducts1 
which  resemble  each  other  in  structure : — 

Spleen,  Thymus, 

Thyroid,  Suprarenal  capsules, 

Pituitary  body,  G-landula   coccygea, 

Glandula  intercarotica. 

The  Spleen  (Lien). — The  spleen  is  a  soft,  very  vascular, 
sponge-like  organ,  situated  deeply  in1  the  left  hypochondriac 
region.  It  varies  much  in  size  and  weight,  measuring  about  five 
inches  in  length,  three  in  width,  one  and  one-half  in  thickness, 
and  weighing  between  seven  and  ten  ounces. 

Outer  surface  (fades  diaphragmatica) ,  smooth  and  convex, 
corresponds  to  the  ninth,  tenth,  and  eleventh  ribs,  and  is 
adapted  to  the  inferior  surface  of  the  diaphragm,  to  which  it  is 
connected  by  the  suspensory  ligament. 

Inner  surface  is  concave  and  adapted  to  the  cardiac  end  of 
the  stomach,  to  which  it  is  attached  by  the  gastrosplenic  omen- 


l  Formerly  it  was  taught  that  these  glands  were  enigmatic  in 
natiae;  more  recently,  however,  it  was  discovered  that  they  elaborate 
subsr  ices  which  are  added  to  the  blood  and  lymph,  and  which  are 
desigi-  d  "internal  secretions."  These  internal  secretions  play  a 
domin;     ;  role  in  maintaining  a  balance  in  the  economy. 


THE  ALIMENTARY  APPARATUS.  251 

Hilus  (hilus  lienis)  is  a  vertical  fissure  on  the  concave 
inner  surface,  admitting  the  passage  of  blood  vessels,  lymphatics 
and  nerves.  The  structure  consists  of  two  coats — a  serous  and 
fibroblastic  coat,  inclosing  in  its  interior  the  spleen  pulp. 

Serous  coat  (tunica  serosa),  derived  from  the  peritneoum, 
covers  the  entire  organ,  except  at  the  hilus,  where  it  forms  the 
gastrosplenic  omentum. 

Fibroblastic  coat,  or  tunica  propria  (tunica  albuginea),  sur- 
rounds the  organ,  and  from  the  hilus  and  periphery  sends 
numerous  fibrous  bands,  or  trabecular  (trabecule  lienis),  into 
the  substance  of  the  organ,  dividing  it  into  small  trabecular 
spaces,  or  areola?. 

Splenic  substance,  or  spleen  pulp  (pal  pa  lienis),  is  a  soft, 
reddish-brown  mass,  consisting  of  a  fine  reticulum  of  connec- 
tive-tissue corpuscles,  inclosing  red  and  white  blood  corpuscles, 
nucleated  and  non-nucleated  cells,  granular  matter,  etc. 

Malpighian  corpuscles,  or  bodies  (noduli  lymphatici  lien- 
ales  [Malpighii]),  are  spheroidal  hyperplasia?  of  lymphoid  tissue 
from  the  outer  coat  of  the  arterioles.  They  are  not  encapsuled, 
vary  from  one-sixtieth  to  one-twenty-fifth  of  an  inch,  and  are 
visible  in  the  fresh  specimens  to  the  naked  eye. 

Splenic  artery,  remarkable  for  its  size  and  tortuosity, 
divides  in  the  hilus  into  four  or  five  branches,  each  distributed 
to  a  segment,  terminating  in  a  capillary  plexus  without  anasto- 
moses, or  opening  directly  into  the  areola?  of  the  splenic  pulp. 

Splenic  rein  commences  in  the  same  manner  as  the  arte- 
rioles end,  and  empties  into  the  portal  vein.  The  smaller  veins 
anastomose  freely. 

Nerves  are  from  the  splenic  plexus,  formed  from  the  right 
pneumogastric  nerve,  and  the  left  semilunar  ganglion  of  the 
solar  plexus. 

Thyroid  Gland  (glandula  thyreoidea) . — The  thyroid  is  a 
vascular,  gland-like  body,  situated  on  the  sides  of  the  upper  part 
lit'  i he  trachea,  and  consists  of  two  lateral  lotjes  connected  by  a 
transverse  portion,  the  isthmus  (isthmus  glandules  thyreoidea). 

A  third  loin — the  pyramid — sometimes  arises  from  the  left 
lobe  or  upper  margin  of  the  isthmus. 

Levator  glanduke  thyreoidea  are  muscular  bands  sometimes 
found  passing  from  the  isthmus  to  the  body  of  the  hyoid  bone. 

Structure. — This  is.  similar  to  other  glands,  being  made  w 
of  a  capsule  and   radiating  septa  inclosing  alveoli     the  closf 
resides — each   of  which    is   lined    with    one   layer  of  colunr  t 
epithelium,  and  contains  more  or  less  viscid,  transparent  flu 
the  coftoid  substance.    The  closed  vesicles  are  abundantly    up 


252  HUMAN   ANATOMY. 

plied  with  blood  by  meshes  of  capillaries,  while  penetrating  the 
septa  are  lymphatic  networks,  and  lymph  sinuses  are  found  in 
the  tissue  between  the  vesicles  and  septa. 

Arteries  are  the  superior  thyroid,  a  branch  of  external 
carotid,  and  inferior  thyroid,  a  branch  of  the  thyroid  axis,  and 
sometimes  a  branch  from  the  arch  of  the  aorta  or  innominate 
artery,  the  middle  thyroid,  or  arteria  thyroidea  ima.  All  the 
vessels  anastomose  freely. 

Veins  form  plexus  about  the  gland  and  give  off  the  superior 
and  middle  thyroid  to  internal  jugular,  and  inferior  thyroid  to 
innominate  vein. 

Nerves,  from  middle  and  inferior  cervical  ganglia  and  from 
pneumogastric. 

Thymus  Gland. — The  thymus  gland  is  a  temporary  organ 
which  attains  its  full  size  at  the  end  of  two  years  and  at  puberty 
has  almost  disappeared.  It  occupies  the  upper  part  of  the  an- 
terior mediastinum,  and  is  in  relation  in  front  with  the  sternum, 
and  below  with  the  pericardium,  aorta,  left  innominate  and 
trachea.  It  is  a  flat,  triangular  body,  composed  of  a  pair  of 
lateral  unequal  lobes,  about  two  inches  in  length,  one  and  one- 
half  inches  at  the  widest  part,  and  one-quarter  inch  thick,  and 
weighing  about  one-half  ounce. 

Structure. — It  is  composed  of  a  framework  of  fibroconnec- 
tive  tissue,  consiting  of  a  capsule,  septa  and  gland  substance, 
which  is  divided,  into  lobes,  these  into  lobules,  and  these  latter 
into  units  or  follicles. 

The  follicles  vary  in  shape,  present  for  study  a  cortex  and 
medulla,  and  consist  of  adenoid  tissue. 

The  cortical  meshes  of  the  reticulated  adenoid  tissue  are 
filled  with  lymph-corpuscles,  while  in  the  medulla  the  meshes 
are  less  numerous  and  filled  with  large  endothelioid  plates  and 
giant  cells. 

The  capillary  blood-vessels  surrounded  the  follicles. 

Arteries  are  from  superior  and  inferior  thyroid  and  inter- 
nal mammary. 

Veins  join  thyroid  and  left  innominate  veins. 

Nerves  are  from  sympathetic  and  pneumogastric. 

Suprarenal  Capsules  (glandulce  suprarenalis) . — The  su- 
prarenal capsules  are  two  small,  triangular  bodies,  situated  upon 
the  upper  and  front  part  of  either  kidney.  They  measure  from 
one  ;;nd  one-quarter  to  two  inches  in  length,  and  less  in  breadth, 
two  lc  three  lines  in  thickness,  and  weigh  about  two  drachms. 


THE  ALIMENTARY  APPARATUS.  253 

Structure. — Like  the  kidneys,  they  consist  of  a  cortical  and 
medullary  portion,  inclosed  in  a  capsule  which  sends  septa  into 
the  substance  of  the  body. 

The  cortex  (substantia  corticalis)  is  composed  of  three 
zones  of  epithelial  cells — outer,  middle  and  inner — the  middle 
being  the  largest. 

The  medulla  (substantia  medullaris)  consists  of  streaks  of 
small,  transparent  cells,  separated  by  connective  tissue  and  capil- 
laries. These  streaks  are  continuous  with  the  inner  zone  of  the 
cortex.  The  nerve  supply  is  rich,  consisting  of  non-medullated 
fibers  connected  with  small  ganglia. 

Relations. — The  inferior  concave  border  rests  upon  the  upper  sur- 
face of  the  kidney.  The  inner  border  rests  against  the  inferior  vena 
cava  on  the  right  side,  the  aorta  on  the  left,  and  is  in  relation  with  semi- 
lunar ganglion  and  great  splanchnic  nerves. 

The  anterior  surfaces  touch  on  the  right  the  under  surface  of  the 
liver,  and  on  the  left  side  the  pancreas  and  spleen.  The  posterior  sur- 
face lies  upon  the  cms  of  the  diaphragm,  about  opposite  the  tenth  dorsal 
vertebra. 

Arteries  are  suprarenal  from  the  aorta,  the  renal  and 
phrenic  arteries. 

Veins  on  the  right  join  vena  cava,  on  left  renal  vein. 

Nerves,  from  renal  and  solar  plexus. 

Pituitary  body  (hypophysis  cerebri)  is  a  small,  vascular 
mass  on  the  inferior  surface  of  the  cerebrum,  but  resembling  in 
structure  the  ductless  glands. 

Structure. — The  upper  lobe  is  part  of  the  central  nervous 
system.  The  lower  and  larger  lobe  has  a  fibrous  capsule  which 
sends  processes  into  the  interior,  forming  minute  septa  ;  these 
divide  and  reunite  around  spaces  called  alveoli.  The  alveoli 
contain  epithelial  cells  of  various  shapes,  between  which  are 
small  irregular  cells  having  flattened  nuclei. 

The  glandula  coccygea  (glomus  coccygeum),  lying  near 
the  tip  of  the  coccyx,  and  the  intekcarotica,  or  carotid  gland 
or  body  (glomus  caroticwin) ,  at  the  angle  of  bifurcation  of  the 
common  carotid,  have  been  recently  included  among  the  duct- 
glands.  They  were  both  discovered  by  Luschka.  The 
framework  of  their  bodies  is  identical  with  that  of  other  glands, 

excepl   that   the  septa  contain   noii-st  riped  muscular  tissue.     The 

alveoli  are  filled  with  gland  substance,  consisting  of  connected 
masses  of  epithelial  cells,  having  in  their  center  a  twisted  capil- 
lary blood  vessels. 


VOCAL  AND  RESPIRATORY  APPARATUS. 


The  lartio;  is  a  musculocartilaginous  box  at  the  top  of 
the  trachea,  below  the  root  of  the  tongue  and  the  hyoid  bone, 
and  is  the  organ  of  the  voice.  It  is  composed  of  cartilages 
(cartilagines  laryngis)  connected  by  ligaments,  provided  with 
muscles,  blood-vessels  and  nerves,  and  lined  with  mucous  mem- 
brane. The  cartilages  are  nine  in  number,  three  single  and 
three  pairs: — 

Thyroid, 

Cricoid, 

Epiglottis, 

Two  arytenoid, 

Two  cornicula  laryngis, 

Two  cuneiform. 

The  thyroid  {cartilago  thyreoidea) ,  the  largest  cartilage, 
consists  of  two  quadrilateral  halves,  united  in  front  in  the 
median  line,  or  entering  angle  of  the  thyroid,  the  upper  part  of 
which  is  the  pomum  Adami  {prominentia  laryngea).  The  outer 
surface  is  marked  by  an  oblique  ridge  (linea  obliqua)  for  the 
attachment  of  muscles.  The  inner  surface  is  smooth  and  cov- 
ered by  mucous  membrane,  and  has  in  front  attached  the  true 
and  false  vocal  cords.  The  posterior  angles  are  prolonged  into 
superior  (cornu  superius)  and  inferior  horns  (cornu  inferius), 
the  superior  giving  attachment  to  the  thyrohyoid  ligament,  the 
inferior  articulating  with  the  sides  of  the  cricoid  cartilage. 

The  cricoid  cartilage  [cartilago  cricoidea)  resembles  a  seal 
ring,  narrow  in  front,  or  anterior  portion  {arcus  cartilaginis 
cricoidea),  the  back  part  of  the  upper  border  articulates  with 
the  arytenoid  cartilage,  and  on  each  side  externally  are  two 
facets  for  the  articulation  of  the  inferior  horns  of  the  thyroid. 

The  epiglottis  {cartilago  epiglottica)  is  a  spoon-shaped, 
fibrocartilaginous  plate,  large  above,  its  narrow  inferior  extrem- 
ity is  prolonged  and  attached  by  a  band  of  fibroelastic  tissue  of 
thyroepiglottic  ligament  {ligamentum  thyreoepiglotticum)  to 
the  thyroid  cartilage.  It  is  also  attached  to  the  posterior  sur- 
face of  the  hyoid  bone  by  the  hyoepiglottic  ligament  {ligamen- 
tum hyoepiglotticum).  The  anterior  or  lingual  surface  has 
three  reflections  of  mucous  membrane  between  it  and  the  tongue 

(254) 


VOCAL    AND    RESPIRATORY    APPARATUS.  255 

{plica-  ^lossoepiglotticce) ,  called  the  glossoepiglottidean  liga- 
ments (ligaiueittum  glossoepiglotticum ). 

The  arytenoid  cartilages    (cartilagines  arytwnoidea)    each 

resembles  the  mouth  of  a  pitcher,  from  which  they  are  named. 
They  are  smaller  than  the  other  two,  and  are  situated  on  the 
summit  of  the  cricoid  cartilage  posteriorly.  They  are  three- 
sided,  the  apex  extends  backward,  and  is  surmounted  by  the 
supra-arytenoid,  cornicula  laryngis,  or  cartilages  of  Santorini 
( cartilagines  corniculatce) . 

The  posterior  surface  has  attached  to  it  the  arytenoid  mus- 
cle. The  anterior  surface  has  attached  to  it  the  thyroarytenoid 
muscle  and  the  false  vocal  cord.  The  internal  surfaces  are 
opposed  to  each  other  and  supplied  with  mucous  membrane.  Of 
the  three  angles  at  the  base,  the  outer  gives  attachment  to  the 
cricoarytenoid  muscle,  lateral  and  posterior.  The  anterior  (pro- 
ms vocalis)  is  prolonged  for  attachment  of  the  true  vocal 
cord. 

The  cuneiform  cartilages  (cartilagines  cuneiformes),  or 
cartilages  of  Wrisberg,  are  two  small  rod-shaped  bodies  extend- 
ing upward  from  the  arytenoid  cartilages  into  the  arytenoepi- 
glottidean  fold  (plica  aryepiglottica) . 

The  cartilages  of  the  larynx,  with  the  exception  of  the 
epiglottis,  are  composed  of  true  cartilage. 

The  LIGAMENTS  of  the  LARYNX  are  divided  into  two  sets — 
the  extrinsic,  those  connecting  the  epiglottis  and  thyroid  car- 
tilage with  the  hyoid  bone,  and  the  intrinsic,  those  which  con- 
nect" the  various  cartilages  together.  The  extrinsic  consist  of 
three : — 

1.  Thyrohyoid  membrane  [membrana  hyothyreoidea) .  connecting 
the  upper  border  of  the  thyroid  cartilage  with  the  inner  surface  of  the 
hyoid  bone; 

2  and  3.  The,  two  lateral  thyrohyoid  ligaments   (Ugamewtvm  hyo- 
thyreoideum   laterale),   ftbroelastic  cords  connecting  the  superior  horns 
the  thyroid  cartilage  with  the  extremities  of  the  great  horns  of  the 
hyoid  bone.     They  contain  a  small  aodule,  bhe  cartilago  triticea. 

The  intrinsic  ligaments  are  sixteen  iii  number,  as  follows: — 

Hyoepiglottic  ligament ; 
Cricothyroid  membrane; 
Two  cricothyroid  capsular  ligaments; 
Two  cricoarytenoid  Ligaments; 
Two  cricoarytenoid  capsular  ligaments; 
Two  superior  thyroarytenoid  ligaments  (in  false  cords); 
o  inferior  thyroarytenoid  ligaments   (in  true  cords); 
Thyroepiglotl  i<-  ligamenl ; 
Three  gloMoepiglottic  folds. 


256 


HUMAN    ANATOMY. 


The  hyoepiglottic  ligament  (ligamentum  hyoepiglatticum) 
is  a  fibre-elastic  band,  connecting  the  anterior  surface  of  the 
epiglottis  with  the  upper  border  of  the  hyoid  bone.  The  liga- 
ments connecting  the  cricoid  to  the  thyroid  cartilage  are  three 
also — the  cricothyroid  ligament,  capsular  ligaments  and  syno- 
vial membranes. 

The  cricothyroid  membrane  (conus  elasticus),  a  yellow, 
elastic  band,  connects  the  adjacent  margins  of  the  cricoid  and 
thyroid  cartilages,  and  extends  from  the  upper  border  of  the 
cricoid  cartilage  to  the  lower  margin  of  the  true  vocal  cords. 


Fig.  94. 

Vertical  section  of  larynx:  1,  body  of  hyoid  bone;  2,  epiglottis; 
3,  thyrohyoid  membrane;  4,  great  cornu  of  hyoid;  5,  false  vocal  cord; 
6,  thyrohyoid  ligament;  7,  ventricle  of  larynx;  8,  thyrohyoid  mem- 
brane; 9,  true  vocal  cord;  10,  arytenoepiglottidean  fold;  11,  thyroid 
cartilage;  12,  superior  cornu  of  thyroid;  14,  arytenoid  muscle;  16, 
arytenoid    cartilage;    18,    cricoid    cartilage. 

The  two  cricothyroid  capsular  ligaments  (articulatio  crico- 
tliyreoidea)  surround  the  articulations  between  the  inferior 
horns  of  the  thyroid  and  the  cricoid  cartilage. 

The  synovial  membrane  (capsida  articularis  cricothyre- 
oidea)  lines  the  capsular  ligaments,  forming  a  true  enarthrodial 
joint. 

The  ligaments  of  the  epiglottis  are  the  thyroepiglottic 
{ligamentum  thyreoepiglotticum) ,  the  hyoepiglottic  (ligamen- 
tum,  hyoepiglotticum) ,  and  the  three  glossoepiglottic  folds 
(plicce  glossoepiglotticce)  of  mucous  membrane  before  described. 


VOCAL    AND    RESPIRATORY    APPARATUS.  257 

The  superior  aperture  (ad Hits  laryngis)  of  the  larynx  is  a 
triangular  opening  with  the  apex  in  front.  It  is  hounded  behind 
by  the  apices  of  the  arytenoid  cartilages  and  corniculse  laryngis, 
in  front  by  the  epiglottis,  and  laterally  by  the  arytenoepiglot- 
tidean  folds.  From  this,  as  its  superior  boundary,  the  cavity  of 
the  larynx  extends  as  low  as  to  the  lower  border  of  the  cricoid 
cartilage.  The  true  vocal  cords  and  the  thyroarytenoid  muscle 
divide  It  into  two  parts,  the  narrow  fissure  between  the  two  cords 
being  called  the  chink  of  the  glottis  (rima  glottidis). 

The  superior  or  false  vocal  cords  (jdiar  ventricular es)  arc 
two  folds  of  mucous  memhrane  inclosing  the  superior  thyro- 
arytenoid Ligaments  (ligamenium  ventricular e) . 

The  inferior  or  true  vocal  cords  (plica  vocalis)  are  two 
folds  of  mucous  memhrane  inclosing  the  inferior  thyroarytenoid 
Ligaments,  composed  of  elastic  tissue,  from  the  sides  of  the  upper 
border  of  the  cricoid  cartilage,  extending  upward  to  the  hases  of 
the  arytenoid  cartilages,  and  lower  portion  of  the  angle  of  the 
thyroid.  Their  upper  margins  correspond  to  the  lower  edges  of 
the  ventricles  of  the  Larynx. 

The  ventricle  of  the  larynx  (vcntriculus  laryngis  [Mor- 
gagnii])  is  a  deep  fossa  on  either  side  of  the  larynx,  bounded 
above  by  the  false  vocal  cords,  below  by  the  inferior  or  true 
■  I  cords,  and  externally  by  the  thyroarytenoidens  muscle. 
The  sacculus  laryngis  (appendix  ventriculi),  or  laryngeal 
pouch,  is  a  membranous  sac  lined  with  mucous  memhrane,  open- 
ing into  the  anterior  portion  of  the  ventricle  of  the  larynx.  Its 
inner  or  laryngeal  surface  is  covered  by  the  arytenoepiglot- 
tideus  inferior  (compressor  sacculi  laryngis  [Hilton]),  and  the 
outer  side  by  the  thyroepiglottideus  and  thyroarytenoideus  mus- 
cles.  It  is  compressed  by  these  muscles,  discharging  its  mucous 
secretion  upon  the  true  vocal  cords. 

MusciJES. — The  intrinsic  muscles  of  the  larynx  consist  of 
two  sets,  live  connected  with  the  vocal  cords  and  rima  glottidis, 
an. I  tlncc  with  the  epiglottis.  The  five  muscles  of  the  vocal 
cords  are: — 

|  ricothyroid  (m.  cricothyreoideus) . — Origin,  from  the 
front  and  Bides  of  the  cricoid  cartilage;  insertion,  into  anterior 
border  of  the  inferior  cornua,  and  lower  margin  of  the  thyroid 
cartilage;  action,  elongates  and  renders  tense  the  vocal  cords; 
nerve,  superior  Laryngeal. 

i  ricoarytcmotdeus  Posticus  (m.  cricoarytcenoidus  poste- 
rior).    -Origin,    from    the    sides    and     posterior    surface    of    the 

cricoid  cartilage;  Insertion,  into  the  outer  angle  of  the  base  of 
arytenoid  cartilage;  action,  rotate-  the  arytenoid  cartilages  out- 

17 


258  HUMAN    ANATOMY. 

ward,  opening  the  glottis,  and  rendering  tense  the  vocal  cords; 
nerve,  recurrent  laryngeal. 

Cricoarytcenoideus  Lateralis  (m.  cricoarytcenoideus  later- 
alis).— Origin,  from  npper  and  outer  side  of  the  cricoid  carti- 
lage; insertion,  in  front  of  the  preceding  into  the  outer  angle  of 
the  base  arytenoid;  action,  rotates  the  arytenoids  inward,  clos- 
ing the  glottis;  nerve,  recurrent  laryngeal. 

Arytcenoideus. — Origin,,  from  outer  border  and  posterior 
surface  of  one  arytenoid  cartilage;  insertion,  into  the  same  part 
of  the  other — its  fibers  are  oblique  (m.  arytcenoideus  obliquus), 
and  transverse  (m.  arytamoideus  transversus)  ;  action,  by  ap- 
proximating the  arytenoids  closes  the  back  part  of  the  glottis; 
nerves,  superior  and  recurrent  laryngeal. 

Thyroarytamoideus  (to.  tliyroarytanoideus) . — Origin,  from 
the  cricothyroid  membrane  and  lower  half  of  the  entering  angle 
of  the  thyroid  cartilage;  insertion,  into  anterior  surface  and 
base  of  the  arytenoid  cartilage — it  consists  of  inferior  (to. 
vocalis)  and  superior  portions,  the  former  entering  into  the 
formation  of  the  true  vocal  cords;  action,  mainly  relaxes  the 
true  vocal  cords  by  drawing  the  arytenoids  forward;  nerve, 
recurrent  laryngeal. 

The  muscles  of  the  epiglottis  are : — 

Thyroepiglottideus  (to.  tliyreoepiglotticus) . — Origin,  from 
the  inner  surface  of  thyroid  cartilage;  insertion,  into  the  mar- 
gin of  epiglottis  an^L  arytenoepiglottidean  fold;  action,  com- 
press the  sacculus  laryngis  and  depress  the  epiglottis;  nerve, 
recurrent  laryngeal. 

Arytcmoepiglottideus  Superior. — Origin,  from  apex  of 
arytenoid;  insertion,  into  arytenoepiglotticlean  folds;  action, 
constricts  the  superior  laryngeal  aperture;  nerve,  recurrent 
laryngeal. 

Aryto3noepiglottideus  Inferior,  or  Compressor  Sacculi 
Laryngis  of  Hilton. — Origin,  from  middle  of  internal  portion 
of  the  arytenoid;  insertion,  into  upper  and  inner  part  of  epi- 
glottis; action,  compresses  the  sacculus  laryngis;  nerve,  recur- 
rent laryngeal. 

The  lining  mucous  membrane  of  the  larynx  is  continuous 
with  that  of  the  pharynx  and  trachea.  It  forms  the  glosso- 
epiglottic  and  arytenoepiglottic  folds,  adheres  tightly  to  the 
epiglottis,  vocal  cords  and  the  interior  of  the  cricoid  cartilage, 
but  is  more  loosely  attached  to  other  parts.  It  contains  numer- 
ous racemose  glands,  particularly  along  the  posterior  margin  of 
the  arytenoepiglottidean  fold,  and  in  front  of  the  arytenoid  car- 
tilages, where  they  are  called  the  arytenoid  glands.    Its  epithe- 


VOCAL    AND    RESPIRATOR!     APPARATUS.  259 

Hum  is  of  the  ciliated,  columnar  variety  below  the  true  vocal 
cords,  and  above  this  point  in  front  as  high  as  the  middle  of 
the  epiglottis.  The  other  portions  are  covered  by  squamous 
epithelium. 

The  arteries  are  the  laryngeal  branches  from  the  superior 
and  inferior  thyroid,  and  the  cricothyroid  branches  of  the  supe- 
rior thyroid. 

The  veins  join  the  inferior,  middle  and  superior  thyroid 
veins. 

The  lymphatics  enter  the  deep  cervical   -lands. 

The  nerves  are  the  inferior  or  recurrent  laryngeal,  the 
superior  laryngeal  branches  of  the  pneumogastric  and  branches 
from  the  sympathetic  nerve. 

The  superior  laryngeal  supplies  sensation  to  the  larynx.  It 
descends  from  the  inferior  ganglion  of  the  pneumogastric,  lie- 
hind  the'internal  carotid  at  the  side  of  the  pharynx,  and  divides 
into  two  branches — the  internal  laryngeal  pierces  the  thyrohyoid 
membrane  to  supply  the  mucous  membrane  and  arytenoid  mus- 
cle the  external  laryngeal  supplies  the  cricothyroid  muscle. 

The  inferior  or  recurrent  laryngeal,  from  its  origin,  winds 
around  the  subclavian  on  the  right  side  and  around  the  arch  of 
the  aorta  on  the  left  side,  and  ascends  by  the  side  of  the  trachea 
to  the  larynx,  of  which  it  is  the  motor  nerve,  supplying  all  the 
muscles  of  the  larynx  except  the  cricothyroid,  giving  off  in  its 
course  cardiac,  esophageal,  tracheal  and  pharyngeal  branches, 
and  anastomosing  with  the  superior  laryngeal  nerve. 

TRACHEA    AM)    BRONCHI. 

The  trachea,  or  windpipe,  is  a  membranocartilaginous  tube, 

about  four  and  a  half  inches  in  length,  three-quarters  to  one 
inch  in  width,  extending  from  the  fifth -cervical  to  the  upper 
border  of  the  lil'th  dorsal  vertebra.  It  divides  into  two  bronchi 
(hi  fun  alio  trachea),  the  right  (bronchus  dexter),  about  an  inch 
long  and  nearly  at  right  angles,  passing  behind  the  right  pulmo- 
nary artery  on  a  level  with  the  lil'th  dorsal  vertebra;  the  left 
[bronchus  sinister),  narrower,  about  twice  as  long,  passes 
beneath  the  arch  of  the  aorta  on  a.  level  with  the  fifth  or  Bixth 
dorsal  vertebra,  behind  the  lefl  pulmonary  artery.  The  trachea. 
ami  bronchi  are  formed  of  a  series  of  cartilaginous  rings,  incom- 
,it  their  posterior  third,  connected  by  fibroelastic  mem- 
brane, and  lined  by  columnar  ciliated  epithelium.  The  last  ring 
is  triangular,  go  ;i-  to  tit  the  rings  of  the  two  bronchi.  The 
mucous    membrane    contains    numerous    racemose    glands,    the 


260  HUMAN   ANATOMY. 

largest  on  the  posterior  surface,  called  the  tracheal  glands 
(glandulce  tracheales).  The  muscular  fibers  consist  of  two 
layers^  longitudinal,  the  most  external,  and  transverse,  internal, 
both  unstriated. 

Relations. — The  trachea  has  the  following  relations  in  the 
neck : — 

Laterally. 

Lobes  of  the  thyroid  body; 
Carotid  arteries; 
Inferior  thyroid  arteries. 

Anteriorly. 

Skin,  superficial  and  deep  fascia; 

Anterior  jugular  veins; 

Left  innominate  vein; 

Inferior  thyroid  plexus  of  veins; 

Isthmus  of  thyroid  body; 

Arteria  thyroidea  ima    (sometimes). 

Posteriorly. 
Esophagus ; 
Vertebral  column; 
Recurrent  and  inferior  laryngeal  nerves. 

5 

The  following  in  the  thorax : — 

Laterally. 
Pleura; 
Pneumogastric  nerves. 

Anteriorly. 
Sternum ; 

Remains  of  thymus; 
Arch  of  aorta; 

Right  and  left  innominate  veins; 
Left  carotid  artery; 
Deep  cardiac  plexus. 

Posteriorly. 
Esophagus. 

The  arteries  are  derived  from  the  inferior  thyroid  and 
bronchial. 

The  veins  empty  into  the  thyroid  and  bronchial  plexuses. 

The  nerves  are  from  the  pneumogastric  and  sympathetic. 

The  lymphatics  empty  into  the  mediastinal  glands. 

The  bronchi  are  the  continuation  of  the  trachea  from  its 
bifurcation  to  the  hilus  of  the  lung. 


VOCAL   AM)    RESPIRATORY    APPARATUS.  gul 

Eight  bronchus  (bronchus  dexter)  is  shorter,  about  one 
inch  in  length,  placed  more  horizontally,  and  wider.  It  divides 
at  the  hilus  into  three  short  branches,  corresponding  to  the  divi- 
sions  of  the  right  lung. 

Left  bronchus  {bronchus  sinister)  is  longer,  nearly  two 
inches  in  length,  placed  more  obliquely,  and  narrower  than  the 
right.  It  divides  into  two  long  branches  corresponding  to  the 
number  of  lobes. 

The  two  bronchi  subdivide  into  the  bronchial  tubes,  or 
bronchioles,  which  ramify  throughout  the  lungs,  dividing  and 
subdividing  (bronchioli  respiratorii) ,  to  end  finally  in  the  pri- 
mary lobules,  where  they  communicate  with  the  intercellular 
air-passages.  Their  cartilages  consist  of  thin  plates,  distributed 
irregularly  along  the  tubes,  and  in  the  finer  tubes  disappearing 
entirely.  The  mucous  membrane  of  the  bronchi  and  bronchial 
tubes  is  lined  throughout  with  columnar  ciliated  epithelium. 

The  arteries,  veins,  nerves  and  lymphatics  are  the  same  as 
for  the  trachea. 

THE    LUNGS. 

The  lungs  (pulmones),  the  organs  of  respiration,  are  two  in 
number,  occupying  the  lateral  cavities  of  the  chest,  separated 
from  each  other  by  the  heart  and  structures  within  the  medias- 
tinum. They  accurately  fill  the  cavity  of  the  chest  at  all  times, 
and  are  covered  by  the  pleura.  They  are  conical  in  shape,  pre- 
senting each  a  base,  apex,  two  borders,  and  two  surfaces.  The 
apex  {apex  pulmonis)  extends  upward  above  the  level  of  the 
first  rib;  the  base  (basis  pulmonis)  occupies  the  convex  surface 
of  the  diaphragm;  the  external,  or  thoracic  surface  (fades  cos- 
talis),  is  accurately  applied  to  the  wall  of  the  thorax;  the  inner 
surface  (fades  mediastinalis)  is  in  contact  with  the  pericar- 
dium, and  is  marked  by  a  depression,  the  hilum  pulmonis  (hilus 
pulmonalis) ,  at  the  root  of  the  lungs.  The  posterior  border 
rests  on  either  side  of  the  spinal  column,  and  the  anterior  border 
is  thin  and  overlaps  the  pericardium. 

The  root  (radix  pulmonalis)  of  each  lung,  situated  near  its 
middle,  is  composed  of  the  following  structures,  surrounded  by 
;i  reflect  ion  of  pleura  : — 

Bronchus ; 

Pulmonary  artery  -, 

Pulmonary  rains; 

Bronchia  I  glands ; 

Bronchial  vessels; 

Posterior  and  anterior  pulmonary  plexuses  of  nerves; 

I  onnective  I  issue. 


2(52  HUMAN    ANATOMY, 

The  root  of  the  right  lung  is  behind  the  right  superior 
cava  and  the  vena  azygos  arches  over  it.  The  root  of  the  left 
lung  lies  below  and  in  front  of  the  arch  and  descending  aorta. 
The  relative  positions  of  the  pulmonary  veins,  pulmonary  artery 
and  bronchus  on  either  side  are : — 

Both  sides,  from  before  backward — - 

V.  Pulmonary  veins, 

A.  Pulmonary  artery, 

B.  Bronchus. 

Right  side,  from  above  downward — 

B.  Bronchus, 

A.  Pulmonary  artery, 

V.   Pulmonary  veins. 

Left  side,  from  above  downward — 

A.  Pulmonary  artery, 

B.  Bronchus, 

V.  Pulmonary  veins. 

The  weight  of  the  lungs  varies  according  to  many  condi- 
tions. In  the  adult  the  approximate  weight  is  about  forty-two 
ounces,  the  right  being  two  ounces  heavier  than  the  left,  and 
their  total  capacity  about  three  hundred  cubic  inches.  The 
right  lung  has  three  lobes,  the  left  but  two,  of  which  the  lower 
is  the  larger.  The  lungs  in  infancy  are  of  a  pale  rose  color,  but 
later  become  of  a  leaden  hue,  variegated  with  dark  slate  and 
bluish  black.  They  are  highly  elastic,  crackle  on  pressure,  and 
float  in  water,  having  a  specific  gravity  of  0.345  to  0.746.  In 
the  fetus  before  birth,  and  also  in  certain  diseases,  they  sink  in 
water.  The  structure  of  the  lung  consists  of  an  external  serous 
coat,  the  visceral  layer1  of  the  pleura,  a  subserous  areolar  tissue, 
highly  elastic,  and  the  parenchyma,  or  proper  substance  of  the 
lungs.  The  latter  is  made  up  of  small  polyhedral  primary 
lobules,  which  unite  to  form  secondary  lobules,  the  latter  giving 
rise  to  the  markings  on  the  surface.  Both  the  primary  and 
secondary  lobules  are  held  together  by  connective  tissue.  A 
primary,  lobule  represents  the  structure  of  the  entire  organ,  con- 
sisting of  a  bronchiole  (bronchioli)  and  infundibula,  or  air- 
passage,  communicating  with  numerous  air-cells. 

The  air-cells  (infundibula)  are  minute  polyhedral  cavities, 
from  one-two-hundredths  to  one-seventieth  of  an  inch  in  diam- 
eter, separated  from  each  other  by  a  thin  lamina,  and  communi- 
cating freely  with  the  infundibula.  They  vary  much  in  size, 
being  largest  on  the  surface  at  the  thin  borders  and  at  the  apices. 


VOCAL  AND  RESPIRATORY  APPARATUS. 


263 


Bach  air-cell  is  composed  of  the  basemenl  membrane,  lined  with 
squamous  epithelium,  and  surrounded  by  a  minute  capillary 
network  of  blood  vessels,  which  intervene  between  the  terminal 
branches  of  the  pulmonary  artery  and  the  commencement  of  the 
pulmonary  veins.  Between  the  cells  the  capillary  network  forms 
a  single  layer. 

The  pulmonary  artery  conveys  the  venous  blood  1"  the 
lungs  and  terminates  in  the  capillary  network  about  the  air- 
cells,  from  which   proceeds  the  pulmonary  vein,  which   passes 


Fio.  95. 

Heart  and  lungs:  i,  right  ventricle;  '■'.,  right  auricle;  5,  pulmo- 
nary artery;  9,  aorta;  10,  Buperior  cava;  20,  root,  of  lung;  21,  22,  23, 
upper,  middle  and  lower  lobes  of  right  lung;  24,  'J.',,  upper  and  lower 
lobes  of   l<ft   lung. 


along  the  bronchial  tubes  to  the  lefl  auricle  of  the  heart.  The 
bronchial  arteries  Bupply  the  structure  of  the  lungs.  They  are 
<Iiti'v<-<I  from  the  aorta,  and  follow  the  course  of  the  bronchial 
tubes,  tin-  bronchial  veins  returning  the  blood  to  terminate  in 
the  hemiazygos  <<v  superior  intercostal  rein  on  the  left. 

The  lymphatics  are  numerous  and  consist  of  a  superficial 
set  converging  to  the  root  and  a  deep  sei  along  the  course  of 
t!i<'  tubes,  and  both  enter  the  bronchial  glands. 

The  nerves  are  derived  from  the  anterior  and  posterior  pul- 
monary plexuses  of  the  pneumogastric  and  sympathetic,  the  hit- 
ter the  larger.    Ganglia  are  found  upon  these  nervi 


264  HUMAN    ANATOMY. 


THE    PLEURAE. 

Each  lung  is  invested  by  a  delicate  serous  membrane,  the 
pleura,  which  lines  the  internal  wall  of  the  thorax  and  is 
reflected  at  the  root  of  the  lung  over  that  organ.  It  consists 
essentially  of  two  layers,  a  parietal  {pleura  parietalis),  or  pleura 
costalis,  and  visceral  (pleura  pulmonalis) .  It  adheres  accu- 
rately to  the  subjacent  structures,  and  is  called,  from  its  position, 
costal  (pleura  costalis),  diaphragmatic  (pleura  diaphragmatica) , 
mediastinal  (pleura  mediastinalis) ,  and  pulmonary.  The  space 
between  the  two  layers  of  each  pleura,  known  as  the  cavity  of 
the  pleura  (cavum  pleurce),  contains  a  thin,  serous  secretion. 

A  fold  extending  downward  from  the  root  of  the  lung  to 
the  diaphragm  forms  the  so-called  pulmonary  ligament,  or  liga- 
mentum  latum  pulmonis. 

Each  pleura  is  a  closed  sac ;  the  right  is  wider,  shorter  and 
extends  higher  in  the  neck  than  the  left.  They  do  n'ot  meet  in 
the  median  line,  except  opposite  the  upper  part  of  the  gladiolus, 
but  have  a  space  between  them  known  as  the  mediastinum. 

The  arteries  are  from  the  intercostal,  bronchial,  pericardiac, 
internal  mammary,  musculophrenic  and  thymic.  ml 

The  veins  accompany  the  arteries. 

The  lymphatics  are  numerous,  and  empty  into  the  inter- 
costal and  posterior  mediastinal  glands. 

The  nerves  are  from  the  phrenic  and  sympathetic. 

MEDIASTINUM. 

The  mediastinum  is  the  space  left  between  the  two  pleura 
in  the  median  line  b^tweejijthe  sternum_and^vertebral  column, 
and  "contains  the  heart  _  within  its  pericardium  and  all  the 
thoracic  viscera  except  the  lungs.  The  intervals  in  the  media- 
stinum from  their  position  are  named  anterior,  middle,  poste- 
rior and  superior  mediastinal  cavities.  The  boundaries  and 
contents  of  the  four  mediastinal  cavities  are  as  follow: — 

Anterior  mediastinum-,  bounded  in  front  by  the  sternum; 
:'   laterally,  pleura;  behind,  the  pericardium.     It  contains: — 

Triangularis  sterni  muscle;      S 

Remains  of  thymus  gland;         w 

Left  internal  mammary  artery  and  vense  comites;  v^ 

Lymphatic  vessels  from  convex  surface  of  the  liver  ;V 

Areolar  connective  tissue.  «**" 

Middlemediastinum,  bounded  in  front  by  the  anterior 
mediastinum ;  laterally,  by  the  pleura ;  behind,  posterior  media- 
stinum.    It  contains: — 


VOCAL  AND  RESPIRATORY  APPARATUS. 


265 


Ascending  portion  of  aorta;    ■"" 

Superior  vena  cava  ;  •" 

Heart,  inclosed  in  the  pericardium ;  •**" 

Bifurcation  of  trachea  ;  ^-^ 

Pulmonary  artery  and  vein-;;  •"-" 

Phrenic  nerves;  -"-"* 

Arterise  comites  nervi  phrenici,  from  the  internal  mammary.    " 

Posterior  mediastinum,  bounded  in  front  by  the  pericar- 
dium and  root  of  the  lungs;  behind,  vertebral  column;  laterally 
pleura.     It  contains: — 


Esophagus;  •—""■ 
Thoracic  duct;  " 
Descending  aorta ; 
Lymphatic  glands  and  vessels; 


iVena  azygos  major;    *-- 
Vena  azygos  minor;     «-"* 
Superior  intercostal  veins ; 
I'lieiimun-iistric    nerves;      — 


Great    splanchnic   nerves,    x" 

The  sujierior  mediastinum  is  that  portion  of  the  mediasti- 
nal  space  above  the  upper  l)order  of  the  fifth  thoracic  vertebra. 
Tt  is  hounded  in  front  by  the  manubrium  stern i;  behind,  by  the 
upper  dorsal  vertebra;  laterally,  by  the  pleura.     It  contains : — 

Origin  of  sternothyroid  muscle;  ^ 
Origin  of  sternohyoid  muscle;  ^ 
Lower    end    of    the     longus    colli 


muscle;     ^ 
Innominate  artery;     S 
Left   carotid  artery;      "^ 
Subclavian  artery;      ^ 
Transverse  portion  of  the  aorta  ;-^ 
Innominate    veins;     ^- 
Superior  vena  cava;     ,/ 


Left  superior  intercostal  vein;  /" 

Left  recurrent  laryngeal  nerves; 

Cardiac  nerves;  -" 

Pneumogastric  nerves;       " 

Phrenic  nerves ;  ^ 

Esophagus ; 

Trachea;  -** 

Thoracic  duct; 

Remains  of  the  thymus  gland;    " 

Lymphatics.  s 


THE  GENITOURINARY  APPARATUS. 


The  genitourinary  apparatus  consists  of  the  urinary  organs 
and  the  male  and  female  generative  organs. 

THE    URINARY    ORGANS. 

The  urinary  organs  consist  of  the  kidneys,  ureters,  bladder 
and  urethra. 

The  kidneys  (renes)  are  two  glandular  organs,  situated 
deeply  in  the  lumbar  region,  opposite  the  second  or  third  lum- 
bar vertebra  and  last  dorsal,  the  right  a  little  lower  than  the 
left.  They  are  surrounded  by  fat  (capsula  adiposa)  and  held 
in  position  by  the  blood  vessels  and  loose  connective  tissue.  The 
right  kidney  is  in  relation  in  front  with  the  liver,  descending 
portion  of  the  duodenum  and  ascending  colon.  The  left  is  in 
relation  with  cardiac  end  of  stomach,  lower  end  of  spleen,  tail 
of  pancreas  and  descending  colon.  Each  kidney  measures  about 
four  inches  in  length,  two  in  width,  and  one  in  thickness  and 
weighs  from  four  and  one-half  to  six  ounces  in  male,  four  to 
five  and  one-half  in  female.  Their  shape  is  characteristic.  The 
notch  at  the  inner  side  is  called  the  hilus  (hilus  renalis),  and 
communicates  with  the  interior  cavity,  the  sinus,  at  which  the 
blood  vessels,  nerves,  and  ureter  have  their  passage:  The  kid- 
neys have  a  special  fibrous  coat  designated  as  the  true  capsule 
(tunica  fibrosa),  slightly  adherent,  which  extends  into  the  hilus 
and  becomes  continuous  with  the  fibrous  coat  of  the  blood  vessels 
and  ureters.  The  relative  position  of  the  arteries,  veins,  and 
ureter  at  the  hilus  are,  from  above  downward: — 

A.  Artery, 
V.  Vein, 

U.  Ureter;    " 


from  before  backward  : — 


V.  Vein, 
A.  Artery, 
U.  Ureter. 


The  general  structure  of  the  kidney  consists  of  a  cortical 
substance  (substantia  corticalis)  and  a  medullary  substance 
(substantia  medullaris),  the  latter  arranged  into  conical  masses 

(266) 


THE    GENITOURINARY    APPARATUS. 


267 


called  renal  pyramids,  with  their  bases  in  the  cortical  substance. 
and  their  apices,  the  renal  papillae  {papillae  renales),  projecting 
into  the  calices  (calyces  renales)  of  the  pelvis  within  the  sinus 
of  the  kidney  (sinus  renalis).  The  renal  pyramids  of  Malpighi 
(pyramides  renales),  about  ten  to  fifteen  in  number,  correspond- 


Fig.  96. 


Longitudinal  section  of  kidney:  1,  cortex:  2,  medulla:  3,  section 
of  tubulee  in  boundary  layer;  4,  fat  of  renal  sinus;  5,  renal  arteriole; 
A,   branch  of  renal  artery;   0,  renal   calyx;    U,  ureter. 

ing  to  the  fetal  lobules,  are  arranged  into  three  irregular  rows. 

mbstance,  or  parenchyma  of  the  kidney,  is  composed  of 
uriniferoue  tubulee  (tvhuli  renale),  held  together  by  compara- 
tively little  connective  tissue.  The  terminal  orifices  of  these, 
several  hundred  to  each  papilla,  open  on  its  summit. 

Course  of  the  Tubuli  Uriniferi. —  Beginning  at  the  Mal- 
pighian   capsule    (capsvla  glomeruli)    within   the   cortex,  cadi 


268  HUMAN  ANATOMY. 

tubule  pursues  a  very  tortuous  and  complicated  course  before  it 
terminates  in  the  renal  papilla  (papillae  renales),  the  outline  of 
which  is  as  follows  (after  Gray)  : — ■ 

(a)  Neck — the  constricted  portion  below  the  capsule,  before  it  ter- 
minates in  the  renal  papillae, 

( b )  Proximal   convoluted  tube,  \    Within  the  cortical  struc- 

(c)  Spiral  tubule  of  Schachowa,  J  ture. 

(d)  Descending  limb  of  Henle's  loop,  \   Within      the      medullary 

(e)  Henle's  loop,  j  structure. 

...     .  ,.        ,.    ,      j.  tt     ,  ,    ,  f   Partly  in  medullary  and 

(f)  Ascendmg  limb  of  Henle  s  loop,      j  'partly   in  cortical. 

(g)  Irregular  tubule,  | 

(h)    Distal   convoluted  tubule,  >   Cortical  structure. 

(d)    Curved   tubule,  J 

(j)  Straight  collecting  tubule — descends  through  the  medullary 
structure  to  open  by  an  orifice  in  a  renal  papilla. 

The  straight,  collecting  or  receiving  tubes  converge  as  they 
descend,  and  unite  and  reunite  until  there  are  about  one  dozen, 
but  they  vary  from  eight  to  twenty,  one  opening  on  the  summit 
of  each  papilla.  In  the  cortical  portion  they  form  groups,  or 
medullary  rays,  giving  the  appearance  of  conical  masses  in  the 
cortical  substance  with  their  apices  toward  the  periphery — the 
so-called  pyramids  of  Ferrein.  The  tubules  are  composed  of  a 
basement  membrane,  lined  with  pavement  epithelium.  In  the 
neck  the  epithelium  becomes  continuous  with  that  of  the  Mal- 
pighian  capsule,  and  at  the  glomerule  the  wall  is  reflected  upon 
the  inclosed  tuft,  or  Malpighian  corpuscle.  In  other  situations 
the  epithelium  varies  much  in  shape  and  size.  The  renal  arter- 
ies subdivide  at  the  hilus,  cross  the  sinus,  and  enter  the  renal 
substance  between  the  renal  papillae.  They  terminate  in  the 
renal  glomerules,  or  Malpighian  corpuscles.  Each  one  of  these 
remarkable  convolutions  of  capillaries  is  about  one  one-hun- 
dredth of  an  inch  in  diameter  and  inclosed  in  a  pouch-like 
dilatation  of  the  uriniferous  tubules  or  Malpighian  capsule,  or 
capsule  of  Bowman.  The  efferent  vessels  form,  together  with 
others,  a  capillary  network  between  and  around  the  uriniferous 
tubules.  They  are  made  up  of  three  sets:  (a)  the  plexuses 
around  the  tubuli  contorti;  (&)  the  veins  beneath  the  capsule; 
and  (c)  the  plexuses  about  the  apices  of  the  pyramids  of  Mal- 
pighi.  These  form  the  vence  interlobular 'es,  which  join  the  vence 
rectce,  and  together  form  the  renal  veins,  vence  propria?  renales. 
Those  in  the  sinus  unite  together  to  form  the  renal  vein,  and 
open  into  the  inferior  vena  cava,  the  left  crossing  in  front  of 
the  abdominal  aorta. 


THE    GENITOURINARY    APPARATUS. 


269 


T  and  8.  Ascending 
limb  of  lleule  B 
loop  tuba. 


Subcapsular  layer  with- 
out Mai pigbian  cor- 
puscles. 


12.  First  part  of  col- 
lecting tube. 

11.  Distal  convoluted 
tubule. 

A/   A.  Cortex. 

10.  Irregular  tubule. 


3.  Proximal  convo- 
luted tubule. 

9.  Wavy  part  of  as- 
cending limb. 

2.  Constriction  or 

neck. 

4.  Spiral  tubule. 

1.  Malpighian  tuft 
surrounded  by 

Bowman's   capsule. 


8.  Spiral  part  of  as- 
cending limb  of 
Uenle's  loop. 


B.  Boundary  Zone. 
6.  Descending  limb  of 
Uenle's  loop  tube. 


15.  Tubule  of  Bellini.  15 


8.  Honle  s  loop. 


■  C.  Papillary  Zoijk. 


Diagram  of  urinlferous  tubules:  i.  Malpighian  capsule;  2,  proxi- 
mal convoluted  tubule;  2  b,  distal  convoluted  tubule;  '■'•.  descending 
limii  of  Henle's  loop;  i,  ascending  limb  of  Uenle's  loop;  5,  irregular 
tubule;  6,  collecting  tube;  a,  apex  of  pyramid;  6,  base  of  pyramid; 
C,   cortical   portion. 


270  HUMAN    ANATOMY. 

The  ureter  commences  as  a  compressed  pouch,  the  pelvis. 
Within  the  sinus  the  pelvis  divides,  and  subdivides  into  several 
small  funnels,  or  calices\,  each  one  of  which  receives  one  or  two 
projecting  renal  papilla?.  The  calices,  pelvis  and  ureter  are  all 
of  the  same  structure,  consisting  of  a  fibrous  and  unstriated 
muscular  and  a  mucous  coat.  The  fibrous  coat  (tunica  adven- 
titia)  becomes  continuous  with  the  capsule  above  and  below  in 
the  fibrous  structure  of  the  bladder.  The  muscular  coat  (tunica 
muscularis)  ceases  at  the  base  of  the  renal  papillae,  but  the 
mucous  membrane  becomes  continuous  with  that  of  the  urinif- 
erous  tubules.  Its  epithelium  is  of  the  transitional  variety, 
consisting  of  several  layers  of  cells  of  varying  shapes,  resting 
upon  a  basement  membrane. 

The  nerves  are  derived  from  the  renal  plexus  of  the  sym- 
pathetic, formed  by  branches  in  the  semilunar  ganglion,  the 
solar  plexus  and  the  lesser  and  smallest  splanchnic  nerve. 

The  lymphatics  communicate  with  the  lumbar  glands. 

The  ureter  proper  is  a  musculomembranous  tube,  sixteen 
to  eighteen  inches  in  length,  about  the  diameter  of  a  goose  quill, 
extending  from  its  origin  in  the  pelvis  of  the  kidney  to  the 
basal  or  posterior  angle  of  the  vesical  trigone,  which  it  enters 
by  passing  obliquely  through  the  muscular  and  mucous  walls  of 
the  bladder. 

Course- — It  descends  upon  the  psoas  magnus  muscle,  be- 
neath the  peritoneum,  being  crossed  by  the  spermatic  vessels. 
About  the  first  division  of  the  sacrum  it  crosses  the  external  or 
common  iliac  artery,  passing  behind  the  sigmoid  flexure  on  the 
left  and  the  ileum  on  the  right  side,  to  enter  the  pelvis,  where 
it  reaches  the  bladder  within  its  posterior  false  ligament. 

In  the  male  it  passes  behind  the  vas  deferens. 

In  the  female  it  crosses  the  uterine  artery  one-third  to  one- 
half  inch  from  the  cervix  uteri  and  passes  along  the  side  and 
upper  part  of  the  vagina  to  the  bladder  (vide  Vagina). 

Muscles  of  the  Ureters. — Two  oblique  muscles.  Origin. 
behind  the  orifices  of  the  ureters ;  insertion,  into  the  middle  lobe 
of  the  prostate  gland;  action,  they  guard  the  orifices  of  the 
ureters,  and  prevent  the  reflux  of  urine. 

Suprarenal  capsules  (vide  Ductless  Glands). 

THE    BLADDER. 

The  bladder  (vesica  urinaria)  is  a  musculomembranous  sac, 
the  reservoir  for  the  urine,  situated  in  the  anterior  part  of  the 
pelvis,  behind  the  pubes,  in  front  of  the  uterus  and  vagina  in 
the  female,  and  the  rectum  in  the  male. 


THE    GENITOURINARY    APPARATUS.  •>]  \ 

It  measures,  moderately  distended,  five  inches  in  length, 
three  in  width,  and  holds  about  one  pint.  It  consists  of  a  body, 
summit.  base  and  neck. 

The  body  {corpus  vesica)  is  partially  invested  with  peri- 
toneum  behind,  but  in  front  it  is  wanting,  the  body  heing  in 
relation  with  the  symphysis  pubis,  triangular  ligament,  and 
internal  obturator  muscles. 

The  summit,  or  apex  (vertex  vesicce),  is  rounded,  and 
directed  upward  and  forward,  being  connected  to  the  umbilicus 
by  the  urachus,  the  remains  of  the  fetal  allantois,  and  also  by 
the  obliterated  hypogastric  arteries,  one  on  either  side. 

The  space  hounded  by  the  pubic  surface  and  the  sides  of 
the  bladder  uncovered  by  peritoneum,  filled  by  the  rectovesical 
fascia,  is  known  as  the  space  of  Eetzius. 

The  base,  or  fundus  (fundus  vesicae),  in  the  male  is  sit- 
uated upon  a  triangular  space  upon  the  second  portion  of  the 
rectum,  it-  base  formed  behind  by  the  rectovesical  fold,  its  apex 
by  the  prostate  gland,  and  its  sides  by  the  vas  deferens  and 
vesiculae  scminales. 

In  the  female  it  is  situated  in  contact  with  the  cervix  uteri 
and  anterior  wail  of  the  vagina,  adhering  closely  to  the  latter. 
It-  upper  portion  has  a  peritoneal  covering. 

The  neck,  or  cervix  (collum  vesicce),  is  the  contracted  por- 
tion, coin  unions  with  the  urethra.  It  is  encircled  in  the  male 
by  the  prostate  gland,  and  is  directed  obliquely  when  the  in- 
dividual is  in  the  erect  posture. 

The  ligaments  of  the  bladder  consist  of  five  true  ligaments 
derived  from  the  pelvic  fascia  and  the  urachus;  and  five  false 
ligaments  derived  from  the  peritoneum. 

The  true  ligaments  are: — 

Two  anterior  (puboprostatic)  (ligamenta  puboprostatica) , 
two  folds  of  rectovesical  fascia  passing  from  the  pubic  symphy- 
sie  to  the-  cervix  and  upper  surface  of  prostate  gland; 

Two  lateral  folds  of  rectovesical  fascia  connecting  the  lat- 
eral surfaces  of  prostate  gland  with  sides  of  base  of  bladder; 

The  urachus  {ligamentum  umbilicale  medium),  an  obliter- 
ated fetal  structure,  passing  as  a  fibromuscular  cord  from  the 
apei  of  tin;  bladder  to  the  umbilicus. 

The  false  ligaments  are: — 

Two  posterior  ligaments  (plicce  rectovesicales)  are  peri- 
tonea] fold.-  parsing  between  ^ides  of  rectum  in  male,  sides  of 
uterus  in  female,  to  posterolateral  surface  of  bladder,  inclosing 
obliterated  hypogastric  arteries,  ureters,  vessels  and  nerves; 


272  HUMAN    ANATOMY. 

Two  laterals  (Ugamenta  umbilicale  laterales)  are  folds  of 
peritoneum  passing  from  iliac  fossge  to  sides  of  bladder; 

The  superior  (plica  umbilicalis  media)  is  a  single  peri- 
toneal fold  inclosing  the  obliterated  hypogastric  arteries  from 
apex  of  bladder  to  umbilicus. 

The  structure  consists  of  four  coats,  a  serous,  muscular, 
submucous  and  mucous. 

The  serous  coat  (tunica  serosa)  is  derived  from  the  perito- 
neum. It  covers  the  posterior  surface  from  the  ureters  to  the 
summit,  and  is  reflected  from  the  sides  to  the  walls  of  the  pelvis 
and  abdomen. 

The  muscular  coat  (tunica  muscularis)  is  made  up  of 
unstriated  fibers  arranged  in  three  layers: — 

(a)  Longitudinal  external  layer  (stratum  externum), 
named  the  detrusor  urines  muscle; 

(b)  Circular  middle  layer  (stratum  medium),  forming  at 
the  neck  the  sphincter  vesicae; 

(c)  Longitudinal  internal  layer  (stratum  internum). 
The  submucous  or  cellular  coat  (tela  submucosa) ,  made  up 

of  fibrous  and  elastic  tissue,  supports  the  mucous  coat  and  unites 
it  with  the  muscular. 

.  The  mucous  membrane  (tunica  mucosa)  is  smooth  and  of 
a  pale  rose  color.  Its  epithelium  is  continuous  with  that  of  the 
ureters  and  pelvis  of  kidneys;  its  superficial  layer,  large,  tessel- 
lated, polyhedral  cells ;  its  deep  layer  of  club-shaped  and  spindle- 
shaped  cells. 

The  inner  surface  of  the  base  presents  a  triangular  space, 
the  vesical  trigone,  or  trigonum  vesica,  apex  in  front,  formed 
by  the  orifice  of  the  urethra,  its  basal  angles  behind  about  two 
inches  apart,  and  each  about  one  and  one-half  inches  behind  the 
urethral  orifice,  formed  by  the  orifices  of  the  ureters: — 

U 

u   u 

2" 

The  uvula  vesica  is  an  elevation  of  mucous  membrane  pro- 
jecting from  the  floor  near  the  apex  of  the  trigone  into  the 
orifice  of  the  urethra. 

The  arteries  are  the  superior,  middle  and  inferior  vesical, 
with  branches  from  the  obturator  and  sciatic  in  the  male,  and 
branches  from  the  vaginal  and  uterine  in  the  female. 

The  veins  from  the  vesicoprostatic  empty  into  the  internal 
iliac  vein. 


THE    GENITOURINARY    APPARATUS.  273 

Lymphatics  follow  the  course  of  the  vessels  and  enter  the 
lumbar  glands. 

The  nerves  to  the  base  and  neck  are  from  the  third  and 
fourth  sacral,  and  to  the  summit,  from  the  hypogastric  plexus 

of  the  sympathetic. 

GENERATIVE    APPARATUS. 

Male   Organs. 

The  male  organs  of  generation  consist  of  the  testes,  vasa 
deferentia.  vesiculae  seminales  and  penis. 

The  testicles  (testes)  are  two  glandular  bodies  which 
secrete  the  spermatic  fluid,  and  are  suspended  by  the  spermatic 
cords  within  the  scrotum,  the  left  a  little  larger  and  lower  than 
the  right.  They  are  oval,  compressed  laterally,  measure  one  and 
a  half  to  two  inches  in  length,  one  inch  in  breadth,  one  and 
one-fourth  inches  in  their  anteroposterior  diameter,  and  weigh 
from  six  to  eight  drachms. 

They  each  consist  of  a  body,  or  testicle  proper,  and  an 
epididymis.  The  latter  consists  of  a  head  or  globus  major 
{caput  apididymidis) ,  body  or  central  portion  (corpus  epidid- 
ymides) and  tail  or  globus  minor  (cauda  epididymidis) . 

The  scrotum  consists  of  the  skin  marked  in  the  median  line 
by  the  raphe  (raphe  scroti),  formed  by  the  union  of  the  genital 
folds,  and  the  dartos,  a  reddish,  contractile  tissue  which  sur- 
rounds the  testes  and  extends  from  the  raphe  to  the  under  sur- 
face of  the  penis,  forming  the  septum  scroti,  which  divides  it 
into  two  cavities  for  the  testes. 

The  spermatic  cord  (funiculus  spermaticus)  is  made  up  of 
the  following  structures: — 

Externa]  spermatic,  or  intercolumnar  fascia; 

Cremaster  muscle; 

Internal  spermatic  fascia,  or  fascia   propria; 

Yas  deferens; 

Spermal  ic  artery  •. 

Deferentia]  artery  from  superior  vesicle; 

Cremasteric  artery,  from  epigastric; 

Vasa  Bpermatica; 

Lymphatic  vessels; 

Spermatic   plexus  of   nerves    [from    renal   and  aortic   plexuses]; 

Genital  branch  of  genitocrural; 

Scrotal   branch  of  the  ilioinguinal, 

Tt  commences  al  the  internal  abdominal  ring,  passes  ob- 
liquely  through  the  inguinal  canal,  emerges  at  the  external 
abdominal  ring,  descends  into  the  Bcrotum,  and  terminates  at 
the  posterior  border  of  the  testes. 

18 


274  HUMAN    ANATOMY. 

The  external  spermatic  or  intercolirmnar  fascia  is  derived 
from  the  aponeurosis  of  the  external  oblique  muscle.  This  mus- 
cle arises  within  the  inguinal  canal  from  Poupart's  ligament 
and  pubic  spine,  and  descends  along  the  cord  in  loops.  Its 
fibers  are  striated. 

The  cremaster  muscle,  or  cremasteric  fascia  {fascia  cremas- 
terica)  or  middle  spermatic  fascia,  is  derived  from  the  lower 
border  of  the  internal  oblique  and  transversalis  muscle. 

The  internal  spermatic  fascia,  or  fascia  propria,  is  the 
infundibuliform  process  of  the  transversalis  fascia. 

The  proper  coverings  or  tunics  of  the  testicle  are  three — 
tunica  vaginalis,  tunica  albuginea  and  tunica  vasculosa : — 

The  tunica  vaginalis  (tunica  vaginalis  propria  testis)  is  a 
serous  membrane  surrounding  the  testes,  and  at  the  posterior 
portion  is  reflected  on  itself  to  form  a  sac.  The  outer  portion 
of  the  latter  is  loosely  attached,  except  at  the  lower  part  of  the 
testicle,  where  the  gubernaculum  testis  binds  it  down. 

The  tunica  albuginea  is  a  dense,  white  fibrous  structure, 
continuous  at  the  upper  part  with  a  similar  structure  on  the 
epididymis.  At  the  back  part  it  projects  into  the  glandular 
substance  of  the  testicle  to  form  the  mediastinum  testis  (corpus 
Tliglimori) ,  from  which  numerous  imperfect  septa,  called 
trabecule  (septula  testis)  diverge,  and  with  similar  cords  from 
the  tunica  albuginea  serve  to  maintain  the  shape  of  the  gland 
and  divide  it  into  lobules. 

The  tunica  vasculosa  (pia  mater  testis)  lies  within  the 
tunica  albuginea,  and  is  the  source  and  termination  of  the 
blood-vessels  to  the  secretory  substance  of  the  gland,  resembling 
the  pia  mater  of  the  brain. 

The  glandular  structure  of  the  testis  is  divided  into  several 
hundred  (two  hundred  and  fifty  to  four  hundred)  pyramidal 
lobules  (lobuli  testis),  each  one  of  which  consists  of  from  one 
to  three  tubuli  seminiferi  contorti. 

At  the  conical  extremity  of  the  lobules  the  tubules  end  in 
straight  tubes,  vasa  recta,  which  enter  the  mediastinum  to  form 
the  plexus  retiformis.  From  the  upper  part  of  this  the  vessels 
unite  into  from  twelve  to  twenty  vasa  efferentia,  which  pass  out 
of  the  testicle  to  the  epididymis.  Within  the  epididymis  these 
efferent  canals  form  a  series  of  spermatic  cones,  the  coni  vas- 
culosi.  These  end  in  a  coarse,  convoluted  tube,  about  twenty 
feet  in  length,  forming  the  body  and  tail  of  the  epididymis,  and 
ending  in  the  spermatic  duct,  or  vas  deferens  (ductus  deferens). 
These  tubes  are  lined  with  columnar  ciliated  epithelium. 


THE    GENITOURINARY    APPARATUS. 


275 


Fig.  98. 


on  through  bladder,  urethra,  and  testicle:  A,  urethral 
orlfict  /•'  seminal  vesicle;  O,  colliculus  seminalis  or  verumontanum; 
I),  prostatic  utricle;  /.',  orifice  of  ejaculatory  duet;  F,  suspensory 
ligament;  ff,  Cowper's  gland;  //.  bulb  of  corpus  spongiosum;  /, 
corpus  spongiosum;  ./,  urethra;  K,  seminal  plexus;  /-.  testicle;  l/, 
peritoneal  fold;  V  space  oi  Retzius;  O,  corpus  cavernosum;  P,  glans 
penis;  (),  prepuce. 


276  HUMAN    ANATOMY. 

The  vas  aberrans  of  Haller  is  a  spermatic  cone  joining  the 
epididymis,  but  unconnected  with  the  testicle. 

The  hydatids  of  Morgagni  are  one  or  two  pedunculated 
bodies  attached  to  upper  part  of  testis  or  head  of  epididymis, 
and  supposed  to  be  the  remains  of  Muller's  duct. 

Structure  of  the  Tubules. — The  tubuli  seminiferi  are  mi- 
nute convoluted  tubules,  closed  at  one  extremity,  consisting  of  a 
hyaline  membrana  propria  lined  with  several  layers  of  epithelial 
polyhedral  cells,  the  seminal  cells,  from  which  the  seminal  or 
spermatic  fluid  is  directly  elaborated. 

These  cells  undergo  a  process  of  indirect  division  (Icaryo- 
hinesis)  to  form  the  spermatoblasts,  which  are  arranged  into 
bundles,  and  are  converted  into  spermatozoids,  the  nuclei  becom- 
ing the  head,  and  the  tail,  or  ciliary  appendages,  being  after- 
ward developed.    These  cells  are  constantly  cast  off  and  replaced. 

Descent  of  the  Testes. — In  early  fetal  life  the  testes  are 
placed  at  the  back  part  of  the  abdomen,  below  and  in  front  of 
the  kidneys,  and  behind  the  peritoneum. 

About  the  third  month  a  peculiar  structure,  the  gubernacu- 
lum  testis,  appears,  attached  to  the  lower  end  of  the  epididymis, 
and  extending  as  a  cord  to  the  bottom  of  the  scrotum.  It  is 
supposed  to  cause  the  descent  of  the  testicle.  It  reaches  its  full 
development  between  the  fifth  and  sixth  month,  at  which  time 
the  testicle  reaches  the  iliac  fossa.  It  enters  the  internal  abdom- 
inal ring  by  seventh  month,  and  the  scrotum  by  the  eighth 
month,  carrying  before  it  a  fold  of  peritoneum,  which  is  after- 
ward shut  off,  forming  the  tunica  vaginalis  testis.  Other  cover- 
ings of  the  testicles  are  also  derived  in  this  manner.  In  the 
female  a  structure  similar  to  the  gubernaculum  forms  the  round 
ligament. 

The  vas  deferens  has  three  coats — (1)  an  external  fibrous 
coat  {tunica  adventitia),  (2)  an  unstriated  muscular  coat 
(tunica  muscularis),  and  (3)  a  lining  membrane  (tunica  mu- 
cosa) of  columnar  epithelium.  It  is  about  one  and  one-half 
feet  long  and  one  line  in  diameter.  From  the  tail  of  the 
epididymis  it  ascends  in  the  cord,  forming  an  important  part, 
and  lying  behind  the  blood-vessels.  It  ascends  through  the 
inguinal  canal,  and  at  the  internal  ring  descends  on  the  bladder, 
crosses  the  ureter  and  obliterated  hypogastric  artery,  and  runs 
forward  to  form  with  the  duct  of  the  seminal  vesicle  the  ejacu- 
latory  duct. 

The  walls  of  the  vas  are  very  thick  and  the  canal  very  small. 
Its  course  for  the  most  part  is  straight,  but  beneath  the  bladder 


THE    GENITOURINARY    APPARATUS. 


277 


it  becomes  enlarged,  tortuous,  arid  more  capacious,  but  again 
contracts  near  its  termination. 

The  arteries  of  the  cord  are: — 

The  spermatic,  to  the  testicle  from  the  aorta: 

The  vas  deferens,  or  deferent  artery,  from  the  superior  vesical; 

The  cremasteric,   from   the  deep  epigastric. 


CREMRS.TER 

MUSCLE. 


Fig.  99. 

The  testicle  and  epididymis:  .4,  testis;  B,  epididymis;  0,  tunica 
vaginalis;  D,  vas  deferens;  /•;,  spermatic  artery  and  veins;  F,  artery 
of  cord. 


The  veins  from  the  testis — spermatic  reins — unite  with 
branches  from  the  epididymis  to  form  the  pampiniform  plexus, 
which  terminates  on  the  Lefl  side  passing  beneath  the  sigmoid 

re  in  the  left  renal  vein,  on  the  right  side  in  the  inferior 

Vlia    I 

The  lymphatics  are  numerous,  and  terminate  in  the  lum- 
bar elands. 


278  HUMAN    ANATOMY. 

The  nerves  are  from  the  sympathetic  system,  and  form  the 
spermatic  plexus. 

The  arteries  of  the  scrotum  are  derived  from  the 

Cremasteric  branch  of  epigastric; 

Superficial  external  pudic,  from  the  femoral; 

Deep  external  pudic,  from  the  femoral; 

Superficial  perineal,  branch  of  internal  pudic,  from  internal  iliac. 

The  seminal  vesicles  (vesiculce  seminales)  are  two  mem- 
branous pouches,  closely  adhering  to  the  under  surface  of  the 
bladder. 

Their  size  varies,  but  they  usually  measure  two  and  one- 
half  inches  in  length,  one-half  inch  in  breadth,  and  two  to  three 
lines  in  thickness. 

Each  consists  of  a  tube  closed  at  one  end,  about  four  to  six 
inches  long,  the  diameter  of  a  quill,  convoluted  into  a  mass.  Its 
structure  is  analogous  to  that  of  the  ducts,  but  thinner. 

The  ejaculatory  ducts  (ductus  ejaculatorii) ,  two  in  num- 
ber, are  formed  by  the  union  of  the  vasa  deferentia  with  the 
duct  of  the  vesiculge  seminales.  Each  duct  is  three-fourths  to 
one  inch  in  length,  and  passes  through  the  prostate  gland  to 
terminate  at  the  margin  of  the  sinus  pocularis  by  a  slit-like 
orifice. 

The  arteries  are  derived  from  the  inferior  vesical  and  mid- 
dle hemorrhoidal.  The  veins  and  lymphatics  correspond  to,  and 
accompany  the  arteries,  and  the  nerves  are  from  the  hypogastric 
plexus  of  the  sympathetic. 

The  seminal  vesicles  are  not  only  reservoirs,  but  secrete  a 
fluid  to  dilute  the  spermatic  liquid. 

The  semen  is  a  viscid,  whitish  liquid,  composed  of  a  color- 
less liquid,  the  liquor  seminis,  and  the  spermatozoa  and  seminal 
granules. 

The  seminal  granules  are  about  one-four-thousandth  of  an 
inch  in  diameter. 

The  spermatozoa  are  the  essential  elements,  and  consist  of 
an  oval  head,  a  body  or  middle  piece  and  a  tail. 

The  penis  is  composed  of  three  columnar  bodies,  two  cor- 
pora cavernosa  and  one  corpus  spongiosum,  invested  with  skin, 
and  filled  with  a  peculiar,  vascular,  sponge-like  structure. 

It  is  attached  to  the  pubic  arch  and  symphysis  by  its  root 
(radix  penis),  has  a  free  expanded  extremity  (glans  penis)  or 
head,  and  an  intermediary  portion,  the  body  (corpus  penis). 

The  upper  surface  is  the  dorsum,  or  back.  The  glans  is  a 
blunt,  cone-like  body,  expanded  at  its  base,  the  corona,  and 
attached  by  its  cervix,  or  neck  (collum  glandis). 


THE    GENITOURINARY    APPARATUS. 


379 


The  summit  has  a  slit-like  aperture,  the  meatus  (orifnum 
urethra  externum),  or  orifice  of  the  urethra. 

The  skin  adheres  loosely  to  the  organ,  and  lias  a  loose,  cup- 
like fold  over  the  glans,  called  the  prepuce  {praspiitmm) ,  after 
which  it  is  reflected  into  the  cervix  and  glans,  becoming  con- 
tinuous with  the  mucous  membrane  of  the  urethra  at  the  meatus, 
to  which  it  is  attached  below  by  a  hand  or  bridle,  the  franum 
(frenulum  prceputii). 


Ttailem  Vajl/tab* 
Tunic*  Afluji a M 


Fig.  100. 
Vertical  section   of   testicle.      (After  Gray.) 

The  ddn  covering  the  glans  resembles  mucous  membrane, 
La  very  rascular  and  sensitive,  hut  about  the  cervix  and  corona 
],;l_  Qumeroufl  preputial  glands— gUndula  Tysom  odonfen 
(glandndce  Tysonii  odoriferce),  which  Becrete  the  smegma. 

The  superficial  fascia  is  thin,  free  from  adipose  tissue,  and 
continuous  with  that  of  the  abdomen  and  scrotum. 

The  suspensory  Ligamenl  (ligamentum  suspensorvum  perns) 
passes  from  the  fronl  of  the  pubic  symphysis  to  the  tunica  al- 
Unnea  of  the  corpora  cavernosa.  The  fundiform  ligament,  or 
li^mentum   fundiforme  penis,  was  formerly  described  as  the 


280  HUMAN   ANATOMY. 

suspensory  ligament;  this  is  not  strictly  correct,  although  the 
latter  ligament  is  suspensory  in  character.  The  ligamentum 
fundiforme  penis  passes  to  the  penis  from  the  lower  part  of  the 
linea  alba,  and  at  its  penile  attachment  divides  into  two  por- 
tions, between  which  pass  the  dorsal  vessels  and  nerves. 

The  corpora  cavernosa  (corpora  cavernosa  penis),  or  cav- 
ernous bodies,  constitute  more  than  two-thirds  of  the  bulk  of 
the  organ.  They  spring  as  crura  from  the  rami  of  the  ischium 
and  pubis,  swell  out  into  the  bulb  of  the  cavernous  body,  or 
corpus  cavernosum,  join  each  other  in  the  median  line,  to  ter- 
minate in  a  conical  extremity,  which  receives  the  glans. 

They  are  grooved  above  for  the  dorsal  vein,  and  below  for 
the  corpus  spongiosum. 

They  each  have  a  strong  outer  fibrous  membrane,  which, 
on  uniting,  forms  a  thick  partition,  complete  behind,  but  incom- 
plete and  comb-like  in  front — septum  pectvniforme. 

From  this  septum  fibroelastic  bands  diverge  in  all  direc- 
tions and  form  trabecules,  which,  with  the  blood-vessels  occupy- 
ing their  intervals,  form  the  erectile  tissue  of  the  corpora 
cavernosa. 

The  corpus  spongiosum  (corpus  cavernosum  urethrce)  com- 
mences as.  a  bulb  below  the  crura  and  in  front  of  the  triangular 
ligament.  It  expands  anteriorly  into  the  glans  penis,  which  fits 
upon  the  conical  termination  of  the  corpora  cavernosa. 

The  urethra  enters  above  and  anteriorly  to  the  bulb  (bulbus 
urethra),  and  traverses  its  entire  length  to  the  summit  of  the 
glans,  opening  at  the  meatus. 

The  corpus  spongiosum  consists  of  an  external  fibrous  coat, 
thinner  and  more  elastic  than  that  of  the  corpora  cavernosa, 
and  an  interior  erectile  tissue.  A  thin,  muscular  layer  lines  the 
external  fibrous  coat,  and  another  is  found  beneath  the  mucous 
membrane  of  the  urethra. 

The  corpora  cavernosa  get  their  blood  from  the  arteries  of 
the  corpora  cavernosa,  and  branches  from  the  dorsal  artery  of 
the  penis,  from  the  internal  pudic. 

The  corpus  spongiosum  is  supplied  by  the  artery  of  the  bulb. 

The  arteries  of  all  three  bodies  terminate  finally  in  the 
erectile  tissue.  Many  arterial  branches,  especially  at  the  root 
of  the  penis,  form  short  convolutions — the  helicine  arteries 
(arteries  helicince),  which  terminate  in  finer  vessels,  and  sub- 
sequently open  into  the  spaces  of  the  erectile  tissue.  Others 
open  directly. 


THE    GENITOURINARY    APPARATUS.  281 

From  these  spaces  the  veins  begin;  some  wind  around  the 
Bide  of  the  organ  to  the  dorsal  vein,  while  others  pass  under  the 
pubis  to  join  the  prostatic  plexus. 

The  lymphatics  are  numerous;  the  superficial  join  the 
inguinal  glands,  the  deep  join  the  lymphatic  plexus  about  the 
prostate  and  other  deep  lymphatics  of  the  pelvis. 

The  male  urethra  (urethra  virilis)  is  the  common  canal 
for  the  emission  of  semen  and  urine,  extending  from  the  neck 
of  the  bladder  (orificium  urethra  internum)  to  the  meatus 
urinarius  (orificium  urethral  externum).  It  is  from  eight  to 
nine  inches  in  length,  and  consists  of  three  portions — the  pro- 
static, membranous  and  spongy. 

The  prostatic  portion  (pars  prostatica)  extends  from  the 
neck  of  the  bladder  to  the  anterior  border  (apex)  of  the  prostate 
gland.  It  is  one  and  one-quarter  inches  in  length,  and  is  the 
widest  and  most  dilatable  part. 

Its  floor  is  raised,  and  presents: — 

Yerumonatum,  or  caput  gallinaginis  (cotticulus  seminalis), 
an  elevated  ridge; 

Prostatic  sinus  (utriculus  prostaticus),  on  each  side  of  the 
verumontanum ; 

Orifices  of  the  prostatic  ducts,  in  the  floor  of  the  prostatic 
sinuses; 

Sinus  pocularis,  a  depression  in  the  median  line  in  front 
of  the  veruniontanum,  presenting  the  slit-like  openings  of  the 
ejaculatory  ducts  (ductus  ejacututorii).  This  cul-de-sac  is  one- 
quarter  of  an  inch  in  length.  It  is  homologous  with  the  uterus, 
and  has  received  the  name  of  utricle,  or  uterus  masculinus. 

The  membranous  portion  (pars  membranacea)  is  about 
three-quarters  of  an  inch  in  length,  extending  from  the  apex 
of  the  prostate  gland  to  the  corpus  spongiosum  above  and  in 
advance  of  the  hull).  It  passes  out  of  the  pelvis  beneath  the 
symphysis  pubis,  traversing  the  triangular  ligament.  It  is  the 
least  di lat ahle  portion  and  has  four  coats: — 

Fibrous,  continuous  with  both  layers  of  the  triangular  liga- 
ment :  erectile,  continuous  with  that  of  the  spongy  body;  an 
iinstriated  muscular  layer  and  a  mucous  coat, 

The  spongy  portion  (pars  cavernosa)  extends  from  the 
membranous  portion  through  the  corpus  spongiosum  to  the 
meatus  urinarius  on  the  summit  of  the  glans. 

The  portion  within  the  hulh  has  received  Ihe  name  of  tudh- 
ous  portion  of  the  urethra.  The  spongy  portion  diminishes 
gradually  in  size  to  near  the  orifice,  where  ii  suddenly  dilates 
into    the    fossa    navicularis     (fossa    navicularis    urethra:    \_Mor- 


282  HUMAN    ANATOMY. 

gagni] ) ,  contracting  again  at  the  meatus,  the  narrowest  part  of 
the  urethra. 

The  mucous  membrane  is  provided  with  columnar  epithe- 
lium, except  near  the  meatus,  where  it  is  tessellated,  a  fibro- 
elastic  submucous  layer  with  unstriated  muscular  fibers,  and 
numerous  minute  racemose  glands,  the  glands  of  Littre  (gland- 
ules urethrales) .  These  latter  open,  forward  into  the  urethra  by 
good-sized  orifices,  especially  one  in  the  upper  part  of  the  fossa 
navicularis,  called  the  lacuna  magna.  Into  the  bulbous  portion 
of  the  urethra  the  ducts  of  Cowper's  glands  open. 

The  prostate  gland  (prostata)  is  a  glandular  body  which 
resembles  in  size  and  form  a  chestnut,  and  surrounds  the  first 
portion  of  the  urethra  between  the  neck  of  the  bladder  and  the 
triangular  ligament.  It  measures  one  and  one-half  inches  in 
length  and  breadth  and  three-quarters  in  depth.  Its  weight, 
about  six  drachms.     Its  flat  under  surface  rests  on  the  rectum. 

It  has  two  lateral  lobes  (lobus  dexter  et  sinister),  and  one 
middle  lobe  (lobus  medius),  which  corresponds  in  position  to 
the  vesicle  uvula,  and  is  held  in  position  by  the  anterior  liga- 
ments of  the  bladder,  by  a  portion  of  the  deep  perineal  fascia, 
and  of  the  levator  ani  muscle. 

It  is  perforated  by  the  urethra  and  the  common  seminal 
ducts. 

Its  structure  consists  of  a  mass  of  flbromuscular  (unstri- 
ated) tissue  with  imbedded  follicular  pouches,  the  whole  inclosed 
in  a  firm  fibrous  capsule,  continuous  in  front  with  the  trian- 
gular ligament,  behind  with  the  posterior  layer  of  the  deep 
perineal  fascia. 

The  muscular  fibers  are  longitudinal  and  circular,  the  lat- 
ter surrounding  the  urethra,  continuous  behind  with  the  blad- 
der, in  front  with  the  fibers  about  the  membranous  portion. 

The  glands  open  into  the  floor  of  the  prostatic  sinuses  by 
twelve  to  twenty  ducts. 

The  arteries  are  from  the  vesical,  hemorrhoidal  and  inter- 
nal pudic. 

The  veins  enter  into  the  formation  of  the  prostatic  plexus, 
receive  the  dorsal  vein  of  the  penis,  and  empty  into  the  internal 
iliac  vein. 

The  nerves  are  from  the  hypogastric  plexus. 

Cowpep/s  glands,  or  suburethral  glands  (glandulce  bulbo- 
uretlirales) ,  are  two  small  lobular  bodies,  about  one-quarter  of 
an  inch  in  diameter,  inclosed  between  the  two  layers  of  the  deep 
fascia,  situated  behind  the  bulb  of  the  corpus  spongiosum,  below 
the  membranous  portion  of  the  urethra.     They  are  racemose 


THE    GENITOURINARY    APPARATUS.  283 

gland-  and  empty  their  secretion  by  a  long  duct  (ductus  excre- 
iorms)  into  the  bulbous  portion  of  the  urethra. 

Female   Organs. 

The  female  organs  of  generation  are  divided  into  the  exter- 
nal (partes  genitales  external  muliebres),  termed  the  vulva,  or 
pudendum,  consisting  of  the  mons  veneris,  labia  majora, 
minora,  clitoris,  meatus  urinarius  and  orifice  of  the  vagina  ;  and 
the  internal   (pars  genitales  internee  muliebris) ,  consisting  of 


Fig.  101. 
Internal   female  genitals. 

the  uterus,  ovaries,  Fallopian  tubes  and  vagina,  with  certain 
accessories. 

The  uterus  is  a  hollow,  muscular  organ  for  the  reception 
of  the  fecundated  ovum  and  the  development  and  expulsion  of 
the  fetus. 

The  virgin  uterus  holds  an  oblique  anterior  position  in  the 
pelvis,  being  supported  by  attachments  to  the  vagina,  rectum, 
bladder  and  sides  of  the  pelvis. 

It  is  in  contact  with  the  bladder  in  front,  the  rectum 
behind,  and  above  the  small  intestine. 

Its  shape  is  pyriform,  compressed  from  before  backward, 
and  measures  three  inches  in  length,  two  in  breadth,  one  in 
thickness,  and  weighs  from  one  to  one  and  a  hall'  ounce-. 

J l  consists  of  a  nock,  fundus  and  body. 


284  HUMAN    ANATOMY. 

The  month,  os  uteri,  or  os  tineas  (orificium  uteri  exter- 
num), open  into  the  vagina,  being  protected  by  two  lips;  an 
anterior  (labium  anterius)  thick  lip,  and  a  posterior  (labium 
posterius),  long  and  narrow. 

The  cavity  of  the  uterus  (cavum  uteri)  is  triangular  V 
from  side  to  side,  but  a  mere  slit  from  before  backward,  and 
measures  two  and  one-half  inches  in  its  longitudinal  diameter. 

The  two  upper  angles  are  prolonged  to  communicate  with 
the  Fallopian  tubes ;  the  lower  angle  forms  the  ostium  internum 
uteri  (orificium  internum  uteri),  communicating  with  the  cav- 
ity of  the  cervix. 

Its  structure  consists  of  three  coats : — 

Serous  coat  (tunica  serosa),  derived  from  the  peritoneum 
and  investing  all  but  the  lower  anterior  quarter ; 

Muscular  coat  (tunica  muscularis),  about  one-half  inch 
thick,  composed  of  unstriated  muscular  fibers  arranged  into 
three  layers; 

Mucous  coat  (tunica  mucosa),  has  numerous  tubular  folli- 
cles, is  lined  with  ciliated  columnar  epithelium,  and  has  no  sub- 
mucous coat  to  connect  it  with  the  muscular  coat. 

The  mucous  membrane  of  the  cervix  is  thrown  into  folds, 
or  ruga},  which  assume  on  the  anterior  and  posterior  walls  a 
branched  arrangement,  or  arbor  viice  uterina.  It  is  lined  by 
squamous  epithelium,  and  presents  numerous  follicular  glands — 
the  ovula  of  Naboth,  or  glandulce  Nabothi. 

The  arteries  are  branches  of  the  ovarian  from  the  aorta, 
and  the  uterine  from  the  internal  iliac,  remarkable  for  their 
tortuosity  and  anastomoses. 

The  veins  form  plexuses  or  uterine  sinuses,  the  branches  of 
which  correspond  to  the  uterine  arteries  and  terminate  in  the 
uterine  plexuses. 

The  lymphatics  are  very  numerous  and  terminate  in  the 
lumbar  and  pelvic  glands. 

-The  nerves  are  from  the  ovarian  and  hypogastric  plexus 
of  the  sympathetic. 

The  ligaments  of  the  uterus  are  foMs  of  peritoneum 
arranged  into  four  pairs: — 

Two  anterior,  or  vesicouterine,  passing  one  on  either  side  from  the 
posterior  surface  to  the  cervix  uteri ; 

Two  posterior  or  rectouterine  {plica  rectouterinw) ,  passing  be- 
tween the  sides  of  the  rectum  and  uterus,  and  inclosing  a  cul-de-sac,  the 
rectovaginal  pouch,  or  Douglas's  pouch; 

A  prolongation  of  this  ligament  upward  to  the  second  sacral  verte- 
bra, with  some  unstriated  muscular  fibers  derived  from  the  uterus  and 
vagina,  forms  the  so-called  uterosacral  ligaments j 


THE    GENITOURINARY    APPARATUS. 


285 


Two  lateral,  or  broad  [Ugamentum  latum  uteri),  extending  from 
the  uterus  to  the  sides  of  the  pelvis,  dividing  it  into  two  portions,  and 
inclosing  the  Fallopian  tubes,  ovary,  ovarian  ligament,  uterine  blood- 
vessels, lymphatics  and  nerves,  and  some  unstriated  muscular  fibers; 

Two  round  ligaments  [Ugamentum  teres),  are  cords  of  unstriated 
muscular  and  fibrous  tissue,  extending  from  the  side  of  the  fundus  uteri 
to  the  inguinal  canal,  where  they  are  lost  in  the  subcutaneous  tissue  of 
the  pubes  and  labia  majora. 

The  canal  of  Nuck,  a  pouch  of  peritoneum,  incloses  the  ligament  in 
the  young  subject,  but  is  usually  obliterated  later. 


„  UreMiro. 


Fig.  102. 
Female  organs  of  generation. 


The  ovaries  correspond  to  the  male  testicles,  and  are  sus- 
pended behind  the  broad  ligament  inclosed  in  its  posterior  layer. 
.They  are  largest  from  puberty  to  adult  age,  and  measure 
one  and  one-half  inches  in  length,  three-quarters  of  an  inch  in 
width,  and  one-third  of  an  inch  in  thickness,  and  weigh  from 
one  to  two  drachms.     The  inner  border  is  attached  to  the  fundus 

uteri  by  the  ova/nan  ligament,  and  its  outer  border  to  the  fim- 
briated extremity  of  the  Fallopian  tube  by  a  cord  (tubo-ovarian 
ligament). 


286  HUMAN    ANATOMY. 

The  structure  of  the  ovary  is  made  up  of  a  reddish,  spongy 
stroma,  well  supplied  with  blood-vessels,  containing  numerous 
ovisacs,  or  Graafian  vesicles  (folliculi  obphori  vesiculori 
[Graafi]),  inclosed  in  a  serous  covering  derived  from  the 
peritoneum. 

The  serous  coat  differs  from  the  peritoneum  in  having  a 
single  layer  of  columnar  cells,  the  germinal  epithelium  of 
Waldeyer. 

The  stroma  of  the  ovary  is  a  vascular  tissue,  composed  of 
many  spindle  cells  and  a  small  portion  of  connective  tissue. 
Upon  the  surface  of  the  ovary,  this  tissue  becomes  niore  firmly 
organized  and  tenacious;  and  was  formerly,  but  erroneously, 
designated  the  tunica  albuginea. 

The  Graafian  vesicles,  or  ovisacs,  containing  the  human 
ova,  vary  in  size  from  microscojfic  bodies  to  one-quarter  of  an 
inch  in  diameter,  and  are  most  abundant  in  the  perijDhery. 

In  structure  they  consist  of  a  fibrous  coat — the  ovicapsule — 
lined  by  a  basement  membrane — membrana  propria — and  a 
layer  of  cells,  the  membrana  granulosa.  The  interior  is  filled 
with  a  transparent  'albuminous  fluid,  liquor  folliculi. 

Tbe  epithelial  lining  nearest  the  ovary  presents  an  accumu- 
lation of  cells — the  germinal  eminence,  or  discus  proligerus, 
within  which  is  the  ovum  or  egg. 

Discharge. — The  Graafian  vesicles  approach  the  surface  of 
the  ovary  and  burst,  their  contents  passing  into  the  opened  aper- 
ture of  the  tube,  the  fimbriated  extremity  apparently  applying 
it  to  the  region  of  the  bursting  ovisac.1 

The  rupture  occurs  periodically  and  corresponds  to  the 
menstrual  flow. 

The  ovum  is  surrounded  by  the  tunica  vasculosa  and  some 
additional  epithelial  structures  (retinacula).  It  is  one-tenth 
line  in  diameter,  and  represents  all  the  elements  of  an  organized 
cell,  being  composed  of  a 

Cell-wall,  or  vitelline  membrane,  or  zona  pellucida; 
Cell-contents,  or  vitellus ; 
Nucleus,  or  germinal  vesicle  ; 
Nucleolus,  or  germinal  spot. 

At  the  seat  of  the  rupture  the  walls  collapse,  and  the 
vesicle  immediately  becomes  filled  with  a  blood-tinged  fluid, 
which,  together  with  the  hypertrophy  of  the  walls,  forms  the 

l  The  fimbriated  extremity  contains  no  erectile  tissue,  and  the 
ovum  probably  falls  into  the  peritoneal  cavity  and  is  swept  into  the 
tube  by  the  action  of  the  cilia.      (Spigelberg.) 


THE    GENITOURINARY    APPARATUS. 


287 


false  corpus  luteum,  which  remains  and  develops  for  two  to 
three  months  and  gradually  disappears. 

Under  the  influence  of  pregnancy  it  enlarges  for  some  time, 
forms  the  true  corpus  luteum  of  pregnancy,  and  disappears  two 
lo  three  months  after  parturition. 

The  arteries  are  the  ovarian  from  the  aorta. 

The  veins  form  an  intricate  plexus  from  which  emerge  ves- 
sels corresponding  to  the*  arteries;  they  form  a  plexus  near  the 
ovary — the  pampiniform  plexus — which  communicates  with  the 
uterine  and  terminates  as  in  the  male. 

The   lymphatics   are   numerous    and   of   large   size    in    the 


FIG.  103. 

Section  of  an  ovary:  e,  germ  epithelium;  1,  large-sized  follicles; 
2,  2,  smaller-sized  follicles;  0,  ovum  within  a  Graafian  follicle;  r,  r, 
blood-vessels  of  the  stroma;   (J,   cells  of  the  membrana  granulosa. 

impregnated  uterus,  and  terminate  in  the  lumbar  and  pelvic 
glands. 

The  nerves  are  from  the  ovarian  and  thoracic  aortic  plexuses 
of  the  sympathetic. 

The  Parovarium,  epo6phoron  or  organ  of  Etosenmuller,  con- 
sists of  a  series  of  tortuous  tubes  extending  from  the  ovary  to  a 
main  transverse  trunk,  near  the  Fallopian  tubes;  and  is  the  re- 
main- of  the  Wolffian  body  of  embryonic  Life,  and  corresponds  to 
the  origin  of  the  epididymis  in  the  male. 

Tin-    Fallopian    tubes,   or   oviducts    {tuba    ulcriiia    FallopU), 

are  the  passageways  for  the  ovum  from  (he  ovaries  to  the  uterus. 


288  HUMAN    ANATOMY. 

They  are  trumpet-shaped  tubes  about  four  inches  long,  with  the 
largest  extremity  outward. 

Its  ovarian  extremity  is  fimbriated;  hence  its  name,  fim- 
briated extremity.  It  is  also  called  morsus  diaboli,  from  its 
supposed  erectile  action. 

One  of  these  fimbriae  extends  along  the  border  of  the  broad 
ligament  to  the  outer  extremity  of  the  ovary,  forming  the  tubo- 
ovarian  ligament  {fimbria  ovarica). 

The  ovarian  orifice — ostium  abdominale,  or  pavilion  (os- 
tium abdominale  tubce  uterince) — is  much  larger  than  the 
uterine,  or  ostium  internum  (ostium  uterinum  tubce). 

The  tube  has  three  coats: — 

Serous  (tunica  serosa),  derived  from  the  peritoneum; 

Fibromuscular  (tunica  muscularis,  stratum  longitudinale 
et  stratum  circular e) ,  from  the  uterine  walls; 

Mucous  coat  (tunica  mucosa),  with  ciliated  columnar  epi- 
thelium, continuous  with  the  uterine. 

The  remains  of  the  duct  of  Mtiller  form  the  hydatid  of 
Morgagni  (appendices  vesiculosi) ,  a  small  vesicle,  attached  by 
a  long  pedicle  near  the  fimbriated,  extremity. 

The  arteries  are  from  the  ovarian,  the  veins  follow  the 
same  course,  and  the  lymphatics  and  nerves  are  the  same  as  the 
ovarian  and  uterine. 

The  vagina  is  a  cylindrical  membranous  canal  extending 
from  the  vulva  to  the  uterus.  It  is  formed  by  the  coalescence 
of  two  symmetrical  tubes  in  fetal  life. 

Relations. — It  is  in  relation  in  front  with  the  base  of  the  bladder 
and  urethra,  behind  its  upper  fourth  with  Douglas's  pouch,  its  lower 
three-fourths  connected  loosely  with  the  rectum,  and  laterally  with  the 
broad  ligaments,  pelvic  fascia  and  levator  ani  muscles. 

On  the  posterior  wall  just  below  the  cervix  uteri  the  -ureters 
approach  each  other,  leaving  a  space  of  only  three-quarters  of 
an  inch  between  them,  an  important  factor  in  lithotomy. 

In  the  virgin  adult  it  measures  about  four  inches  in  length, 
one  inch  in  width,  somewhat  larger  in  its  middle.  Its  anterior 
(paries  anterior)  and  posterior  walls  (paries  posterior)  are  in 
contact. 

Its  lower  orifice,  or  entrance  (orificium  vagina),  is  con- 
stricted by  a  crescentic  or  circular  fold,  of  mucous  membrane, 
the  hymen. 

The  upper  extremity,  or  fundus,  receives  the  cervix  uteri, 
extending  higher  up  posteriorly  (five  to  six  inches),  making 
the  anterior  lip  apparently  the  longest. 


THE    GENITOURINARY    APPARATUS. 


289 


The  mucous  membrane  has  numerous  transverse  folds,  or 
rugae  (rugce  vaginales),  passing  to  either  side  of  a  median  ridge, 
both  anterior  and  posterior,  the  columnae  vagina'  (columnm 
rugdrum  anterior  et  posterior),  formed  by  the  coalescence  of 
the  two  tubes  in  fetal  life.     Some  of  these  rugae  present  wart- 


MONS    VENERIS 


fe? 


<v 


MEATUS 
-URINARIUS 


kJ 


Fig.  104. 
External  female  genitals.     (Eckley.) 


like  eminences,  most  numerous  about  the  entrance  of  the  vagina, 
.where  they  form  the  caruneulae  myrtiformes  {cwrwricvXcB  liyme- 
nales),  the  remains  of  the  hymen   after  intercourse   (or  after 
parturil  ion — Budin). 

The  (trails  of  the  vagina  are  about  one  line  thick  and  con- 
-i-i  of  three  coats: — 

19 


290  HUMAN    ANATOMY. 

Muscular  coat  (tunica  muscularis),  of  unstriated  fibers, 
elastic  tissue  and  blood-vessels,  consisting  of  two  layers,  external 
longitudinal  and  internal  circular,  and  about  the  entrance  the 
internal  circular  fibers  form  the  sphincter  vagince  (vide  Peri- 
neum) ; 

An  erectile  coat,  largely  composed  of  loose  connective  tis- 
sue, imbedded  in  which  are  many  large  veins  and  unstriped 
muscular  fibrous  tissue.  This  erectile  coat  is  found  between  the 
mucous  membrane  and  the  muscular  coat. 

Mucous  or  internal  coat  (tunica  mucosa),  containing  nu- 
merous conical  papillae,  and  covered  by  squamous  epithelium. 

The  arteries  are  from  the  vaginal,  uterine,  vesical  and 
internal  pudic. 

The  veins  form  an  intricate  plexus  on  each  side  with  the 
returning  vessels,  corresponding  to  the  prostatic  plexus,  and  join 
the  internal  iliac  veins. 

The  nerves  are  from  the  hypogastric  plexus  of  the  sympa- 
thetic, also  the  fourth  and  fifth  sacral  and  internal  pudic  nerves. 

The  vulva,  or  pudendum  (pudendum  muliebre) ,  consists  of 
the  mons  veneris,  labia  majora  and  minora,  clitoris  and  meatus 
urinarius. 

The  mons  veneris  (mons  pubis)  is  the  prominence  of  skin 
over  the  symphysis  pubis,  supported  upon  a  mass  of  adipose 
tissue,  and  covered  with  hair. 

The  labia  majora  (labia  majora  pudendi)  are  two  folds  of 
skin  bounding  the  vertical  fissure  of  the  labia  (rima  pudendi), 
the  junctions  of  which  in  front  and  behind  form  the  anterior 
(commissura  labiorum  anterior)  and  posterior  (commissura 
labiorum  posterior)  commissures.  The  labia  correspond  to  the 
scrotum  in  the  male. 

Within  the  posterior  commissure  is  a  depression,  fossa  na- 
vicularis  (fossa  navicularis  veslibuli  vagince),  which  separates  it 
from  a  fold  of  mucous  membrane — the  fourchette  (frenulum 
labiorum  pudendi) . 

The  triangular  space  between  the  anus  and  the  posterior 
commissure  is  termed  the  perineum. 

The  clitoris  corresponds  to  the  penis  in  the  male,  resem- 
bling it  also  in  form,  structure  and  connections. 

It  is  about  one  and  one-half  to  two  inches  in  length,  and 
consists  of  a  pair  of  corpora  cavernosa,  and  a  double,  spongy  . 
body  (corpus  clitoridis),  surmounted  by  a  free  extremity  (glans 
clitoridis) . 

The  corpora  cavernosa  (corpus  cavernosum  clitoridis)  arise 
by  two  crura  attached  to  the  rami  of  the  pubes  and  ischium  like 


THE    GENITOURINARY    APPARATUS.  291 

the  penis,  and  united  in  front  by  the  septum  pectiniforme. 
They  curve  abruptly  down,  being  attached  to  the  pubic  sym- 
physis by  a  suspensory  ligament.  The  body  and  crura  represent 
a  tripod. 

The  free  extremity  (glans  clitoridis)  corresponds  to  that  of 
the  male  penis,  but  is  not  perforated  by  the  urethra.  It  is 
covered  bv  the  praputium  clitoridis,  a  hood-like  fold  of  skin 
continuous  with  the  nymphae. 

The  corpus  spongiosum  consists  of  an  intermediate  portion 
and  semibulbs.  The  former  consist  of  a  plexus  of  veins,  in- 
closed in  a  fibrous  membrane. 

The  semibulbs,  or  bulbi  vestibuli,  are  about  the  size  of  large 
almonds,  and  are  situated  beneath  the  vestibule,  embracing  the 
orifices  of  the  urethra  and  vagina.  In  front  of  the  bulbs,  be- 
tween them  and  the  clitoris,  is  a  smaller  plexus  called  the  pars 
intermedia. 

The  arteries,  nerves,  and  veins  are  the  same  as  those  of  the 
penis. 

The  nymphae,  or  labia  minora  (labia  minora  pudendi),  are 
two  folds  of  mucous  membrane  diverging  from  the  praputium 
clitoridis  to  the  labia,  where  they  are  lost.  At  their  superior 
extremity  they  divide  into  two  folds,  the  upper  forming  the 
prceputium  clitoridis,  the  lower  ones  are  usually  lost  in  women 
who  have  borne  offspring.  In  the  non-pregnant  female  they 
usually  unite  behind,  forming  a  fold,  designated  the  frenum 
(frenulum  clitoridis). 

These  diverging  labia  inclose  a  triangular  space,  the  vesti- 
bule (cestibuliuii  vagina),  at  the  middle  of  the  base  of  which 
is  situated  the  orifice  of  the  urethra,  or  meatus  urinarius, 
(crifi  tin  in  urethra  externum). 

The  bladder  in  the  female  is  larger  and  broader  than  in 
the  male.  It  is  situated  behind  the  pubes,  in  front  of  the 
uterus,  from  which  it  is  separated  by  the  small  intestine,  and 
rests  upon  the  anterior  wall  of  the  vagina  and  cervix  uteri. 

The  urethra  is  a  short  but  capacious  canal,  one  and  one- 
half  inches  in  length,  one-quarter  inch  in  diameter,  extending 
beneath  the  pubic  symphysis  from  the  neck  of  the  bladder  to 
the  externa]  urinary  meatus.  It  lies  in  the  anterior  wall  of  tin' 
vagina,  and  perforates  the  triangular  ligament  precisely  as  does 
the  male  urethra  (vide  Urethra)'. 

Below  the  vestibule  is  the  entrance  or  orifice  of  the  vagina 
(orificium  vagina).  The  mucous  membrane  of  the  labia  is 
reflected  continuously  to  the  clitoris,  aymphse,  prepuce  and 
vestibule,  and  becomes  continuous  with  the  vagina  and  urethra. 


292  HUMAN   ANATOMY. 

Its  epithelium  is  squamous,  and  its  glands  racemose,  mu- 
cous and  small  sebaceous  glands  (glandulce  Tysonii  odoriferce). 

The  Bartholin  or  suburethral  glands  (glandula  vestibularis 
major  [Bartholini])  are  two  racemose  glands  about  one-third 
inch  in  diameter,  situated  just  behind  the  semibulbs  of  the 
spongy  body.  The  ducts,  about  three-fourths  inch  long,  open 
between  the  nymphse  and  the  vaginal  orifice,  or  the  hymen,  if 
present.     They  secrete  mucus. 

The  blood  vessels  and  nerves  of  the  vulva  correspond  to 
those  of  the  penis  and  scrotum  (vide  Internal  Pudic  Artery). 


MAMMARY    GLAND. 

The  mammae,  or  breasts  (mamma),  are  the  milk-secreting 
organs  of  the  female  (being  rudimentary  in  the  male).  They 
consist  of  two  large,  hemispherical  bodies  (corpus  mamma),  in 
the  anterolateral  region  of  the  thorax,  resting  upon  the  pecto- 
ralis  major  muscle,  between  the  third  and  seventh  ribs,  inclosed 
between  the  two  layers  of  the  superficial  fascia. 

The  nipple  (papilla  mammce)  -  is  roseate  or  brownish,  and 
surrounded  by  an  areola  (areola  mamma?)  of  the  same  color, 
the  skin  of  which  contains  numerous  sebaceous  glands,  the 
tubercles  of  the  areola,  or  the  glands  of  Montgomery  (glandulce 
areolares).  The  skin  of  the  nipple  is  thin,  vascular  and  erectile. 
On  its  summit  are  the  orifices  of  the  fifteen  to  twenty  milk- 
ducts,  or  lactiferous  ducts. 

Its  structure  is  firm  and  pinkish  white,  consisting  of  fifteen 
or  twenty  lobes  (lobi  mamma'),  forming  a  racemose  gland,  held 
together  and  invested  with  fibrous  tissue. 

Each  lobe  ends  in  one  of  the  tubuli  lactiferi,  or  galacto- 
phori  (ductus  lactiferus) ,  which  beneath  the  areola  dilates  into 
a  lactiferous  sinus,  or  galactophorus  sinus,  or  ampulla  (sinus 
lactiferans) ,  and  terminates  on  the  summit  of  nipple  in  an 
orifice. 

The  arteries  are,  the  long  thoracic,  with  other  branches  of 
the  axillary,  the  internal  mammary  and  intercostals. 

The  veins  follow  the  corresponding  arteries  to  end  in  the 
internal  mammary  and  axillary  veins.  They  form  about  the 
base  of  the  nipple  a  venous  circular  anastomosis,  the  circulus 
venosus. 

The  lymphatics  terminate  in  the  axillary  glands,  a  few  also 
entering  the  anterior  mediastinal  glands. 


THE    GENITOURINARY    APPARATUS.  293 

The  nerves  are  from  the  fourth,  fifth  and  sixth  intercostal*, 
with  sympathetic  filaments  from  the  dorsal  cord. 

Milk,  the  secretion  of  the  mammary  gland,  is  an  emulsion, 
consisting  of  a  colorless  fluid,  the  mil  I- -plasm  a,  holding  in  sus- 
pension the  milk-globules.  It  has  a  specific  gravity  of  1.028  to 
1.034,  and  slightly  alkaline  reaction. 


THE  NERVOUS  SYSTEM. 


The  nervous  system,  for  description,  is  divided  into  two 
parts :    central  and  peripheral. 

The  central  nervous  system,  cerebrospinal  axis,  or  enceph- 
alospinal  axis,  or  neuraxis,  consists  of  the  brain  and  spinal  cord, 
and  also  comprises  certain  exterior  ganglia. 

The  peripheral  nervous  system  consists  of  the  cranial  and 
spinal  nerves  and  ganglia,  and  the  sympathetic  nerves  and 
ganglia. 

The  nervous  system  may  also  be  divided  into  the  cerebro- 
spinal system,  that  supplying  muscles,  skin,  and  mucous  mem- 
branes; and  the  sympathetic  system,  presiding  over  organs  and 
blood  vessels. 

Structure. — Nervous  tissue  consists  of  three  distinct  sub- 
stances, combined  in  variable  proportions  in  the  different  parts 
of  the  nervous  system  (white,  or  fibrous  substance;  gray,  cineri- 
tious,  or  vesicular  substance,  and  neuroglia).. 

(a)  White  substance  is  found  in  the  cortex  of  the  cord,  the 
interior  of  cerebrum,  in  nerves,  etc.,  and  is  made  up  of  medul- 
lated  nerve  fibers.  These  are  smooth,  round  fibers,  measuring 
one-two-thousandth  to  one-twelve-thousandth  of  an  inch  in 
diameter,  and  have  each  three  parts : — 

1.  Axis  cylinder  of  Purkinje  is  a  round  or  bandlike  striated 
structure  consisting  of  fibrillar,  called  the  primitive  fibrillar  of 
Schultze.  There  is  said  to  be  an  envelope  of  tissue  around,  this 
composed  of  a  substance  called  neurokeratin; 

2.  The  medullary  sheath,  or  white  substance  of  Schwann, 
is  made  up  of  fatty  matter  in  a  fluid  condition  and  probably 
insulates  the  axis  cylinder;  and 

3.  The  neurilemma,  or  sheath  of  Schwann,  a  delicate,  struc- 
tureless membrane,  closely  surrounding  the  medullary  sheath, 
and  forming  the  surface  of  the  nerve  fibers. 

Near  their  termination  the  nerve  fibers  lose  their  medul- 
lary sheath  and  become  non-medullated  (Eemak's)  fibers.  Such 
are  the  olfactory  and  most  of  the  sympathetic  nerves. 

(b)  Gray  substance,  found  in  the  middle  of  the  spinal 
cord,  in  the  cortex  of  the  brain,  in  ganglia,  etc.,  consists  of 

(294) 


THE    NERVOUS    SYSTEM. 


295 


throe  elements:     (1)    nerve  fibers;    (2)    nerve   cells;   and    (3) 
blood  vessels  and  connective  tissue. 

Nerve  fibers. — The  nerve  fibers  are  the  prolongation  of  the 
nerve  cells.  If  there  be  but  one  process  it  is  termed  the  axone, 
axis  cylinder,  or  Dietrich's  process.  If  there  be  more  than  one 
there  is  one  which  is  the  axone  and  the  rest:  are  called  dendrites, 
or  protoplasmic  processes.  There  are  two  kinds  of  fibers,  med- 
ullated  and  non-medullated. 

Nerve  cells  are  of  three  kinds,  according  to  the  number  of 
their  processes:    unipolar,  bipolar  and  multipolar  cells. 

A  neuron  is  the  term  given  to  a  nerve  cell  with  its  axone, 
or  axis-cylinder  process,  and  its  dendritic  processes.  Each  neu- 
ron is  a  distinct  and  separate  unit.  According  to  the  neuron 
theory  the  neurons  mass  together  to  form  cell  groups  and  fiber 
systems.  Each  neuron  is  not  joined  to  the  other  neurons,  but 
is  in  contact  with  them.  Process  touches  process  or  process 
touches  cell.  The.  neuron  theory  is  as  yet  not  firmly  established 
and  a  new  theory,  that  of  Apathy  and  others,  claims  that  the 
chief  constituents  of  the  nervous  system  are  neurofibrils  which 
go  from  cell  to  cell. 

(c)  Neuroglia,  the  supporting  framework  of  nerve  tissue, 
is  made  up  of  a  matrix  of  delicate,  fibrillar  network  and  small 
neuroglia  cells,  and  forms  an  imbedding  substance  for  the  other 
elements. 

Nerves  are  round,  or  flattened  white,  shining  cords,  belong- 
in-  either  to  the  cerebrospinal  or  the  sympathetic  systems. 
They  are  made  up  of  bundles  of  nerve  fibers  held  together  by 
fibroconnective  tissue,  the  epineurium.  The  individual  fibers  are 
held  together  within  the  bundles  by  connective  tissue,  the  endo- 
neurium. 

The  nerve  fibers  have  a  twofold  function — sensory  and 
motor. 

Sensory,  or  afferent,  transmit  impressions  from  the  periph- 
ery to  the  centers. 

Mo/or,  or  efferent,  transmit  impressions  from  the  centers 
io  the  periphery. 

Ganglia  form  independent  nerve  centers,  similar  to  but  Less 
complex  than  the  brain.  They  are  connected  with  some  of  the 
cranial  nerves,  all  of  the  spinal  nerves,  and  form  an  important 
part  of  the  sympathetic  system. 

Terminations.-  The  motor  uerves  end  in  the  voluntary  and 
involuntary  muscles,  the  former  having  special  endings  called 
the  motortal  end  plates. 


296  HUMAN    ANATOMY. 

The  sensory  nerves  terminate  in  the  peripheral  organs  to 
which  they  are  distributed  by  first  becoming  non-medullated, 
and  then  dividing  and  joining  one  another  to  form  a  minute 
plexus  or  by  means  of  one  of  the  five  special  endings,  called 
"peripheral  end  organs":  (1)  tactile  corpuscles  of  Wagner;  (2) 
end  bulbs  of  Krause;  (3)  the  Pacinian  corpuscles;  (4)  neuro- 
tendinous spindles;  or  (5)  neuromuscular  spindles. 

CEREBROSPINAL    AXIS. 

The  cerebrospinal  axis  is  divided  into  two  grand  divi- 
sions : — 

The  encephalon,  or  brain  and  spinal  cord. 

Membranes  of  the  Brain. — The  membranes  of  the  brain 
(meninges  encephali)  are  three — dura  mater,  arachnoid  and 
pia  mater. 

Dura  mater  (dura  mater  encephali)  is  a  dense,  white, 
fibrous  membrane  lining  the  interior  of  the  skull,  and  forming 
its  internal  periosteum,  to  which  it  is  tightly  adherent  at  the 
sutures. 

It  contains  the  sinuses  or  venous  channels  (already  de- 
scribed), and  forms  four  partitions  for  the  support  of  the 
brain — the  falx  cerebri,  falx  cerebelli,  tentorium  cerebelli  and 
diaphragma  sella;. 

Falx  cerebri  is  an  arched  or  sickle-shaped  process  received 
into  the  longitudinal  fissure.  It  contains  in  its  upper  and  lower 
margins  the  superior  (sinus  sagittalis  superior)  and  inferior 
(sinus  sagittalis  inferior)  longitudinal  sinuses  and  forms  by  its 
attachment  to  the  tentorium  the  straight  sinus   (sinus  rectus). 

Tentorium  cerebelli  is  a  lamina,  arched  across,  between  the 
superior  borders  of  the  petrous  portion  of  temporal  on  either 
side,  the  anterior  and  posterior  clinoid  processes  in  front,  the 
transverse ,  ridge  of  the  occipital  behind,  for  the  support  of 
the  posterior  lobes  of  the  cerebrum.  It  incloses  the  superior 
petrosal  (sinus  petrosus  superior)  and  the  lateral  sinuses  (sinus 
transversus) . 

Falx  cerebelli  is  a  small  median,  triangular  partition  de- 
scending from  the  tentorium  to  the  foramen  magnum,  and 
separating  the  lateral  lobes  of  the  cerebellum. 

Diaphragma  sella?  is  a  horizontal  process  formed  by  a  doub- 
ling of  the  meningeal  layer  of  the  dura  mater.  It  forms  a 
small  circular  fold  which  roofs  the  sella  turcica  and  covers  the 
pituitary  body,  leaving  a  small  central  opening  (foramen  dia- 
phragmatic sella:). 


mi-:    NERVOUS    SYSTEM.  297 

The  arachnoid  (arachnoidea  encephali)  is  a  thin,  trans- 
parent, delicate  membrane  consisting  of  fibrous  and  elastic  tis- 
sue, situated  between  the  dura  and  pia  mater.  From  the 
former  it  is  separated  by  the  subdural  space  (cavum  sub- 
durale)  :  from  the  latter,  by  the  subarachnoid  space  {varum  sub- 
arachnoideale ) . 

\  nlike  the  pia  mater,  it  does  not  dip  into  the  sulci  on  the 
brain  surface,  excepl  by  the  Sylvian  and  great  Longitudinal 
fissure-. 

The  subarachnoid  Bpace  contains  cerebrospinal  fluid,  and 
communicates  through  certain  foramina  with  the  cavities  of  the 
brain.  The  space  is  much  broken  up  by  loose  connective  tissue, 
which  connects  it  to  the  pia  mater. 

The  three  expanded  portions  of  the  subarachnoid  space  are 
the  cisterna  magna,  cisterna  pontis  and  cisterna  basalis. 

The  cisterna  magna  (cisterna  cerebellomedullaris) ,  or  pos- 
terior subarachnoid  space,  is  placed  over  the  roof  of  the  lower 
portion  of  the  fourth  ventricle,  and  communicates  with  the 
fourth  ventricle  by  the  foramen  of  Majendie  and  two  smaller 
foramina:   those  of  Keves  and  Retzius. 

Tlie  anterior  subarachnoid  space  (cisterna  pontis)  is  placed 
in  front  of  the  pons  Varolii. 

The  cisterna  basalis  (cisterna  interpeduncularis)  incloses 
the  circle  of  Willis. 

The  Pacchionian  bodies  (granvlationes  arachnoid eales)  are 
projections  of  the  arachnoid  into,  but  not  through,  the  dura 
mater,  and  are  most  numerous  along  the  great  longitudinal 
sinus.  They  make  impressions  on  the  under  surface  of  the  cal- 
varium.  from  which,  however,  they  are  separated  by  a  thin  layer 
of  dura  mater.  Their  function  is  to  allow  the  passing  of  fluid 
from  the  subarachnoid  space  into  the  brain-sinuses  when  the 
blood  pressure  in  the  Binusee  is  lower  than  in  the  subarachnoid 
space. 

Pia  mater  (pia  mater  encephali),  the  investing  membrane 
of  the  brain,  is  composed  of  a  network  of  blood  vessels  derived 
from  the  vertebral  and  internal  carotid  arteries,  held  together 
by  delicate  connective  tissue.  It  dips  into  the  sulci,  and  is  pro- 
longed into  the  ventricles,  forming  the  velum  interposition 
(tela  chorioidea  ventricidi  tertvi)',  or  tela  choroidea  superior  and 
the  tela  choroidea  inferior  (tela  chorioidea  ventriculi  quarti). 
The  former  covers  the  third  ventricle  and  extends  into  the 
lateral  ventricles,  carrying  in  its  margins  the  choroid  plexus  of 
the  lateral  ;md  third  ventricles.  It  is  perforated  by  two  slitlike 
foramina,  one  communicating  with  each  lateral  ventricle. 


298 


HUMAN    ANATOMY. 


The  tela  choroidea  inferior  (tela  choroidea  ventriculi 
quarti)  forms  the  roof  of  the  lower  part  of  the  fourth  ven- 
tricle.    It  contains  nerves  and  lymphatics. 

The  Beain  (The  Encephaixw) . 

The  brain  (enceplialon)  consists  of  four  distinct  portions: 
the  cerebrum,  cerebellum,  pons  Varolii  and  medulla  oblon- 
gata. The  average  weight  of  the  brain  in  the  male  adult  is 
forty-nine  and  a  half  ounces,  in  the  female  forty-four  ounces,' 
of  which  the  cerebrum  is  about  seven-eighths  of  total  weight. 
The  maximum  male  brain  weighs  sixty-five  ounces;  minimum, 
thirty-four  ounces.  The  maximum  female  brain  weighs  fifty-six 
ounces;  minimum,  thirty-one  ounces.  The  brains  of  idiots  sel- 
dom weigh  more  than  twenty-three  ounces.  Excepting  the  whale 
and  elephant,  the  human  brain  is  heavier  than  that  of  all  the 
lower  animals. 

The  brain  is  developed  from  the  anterior  portion  of  the 
primitive  neural  tube.  This  expands  and  later  becomes  con- 
stricted into  three  primary  brain-vesicles,  which  are  called  the 
fore-brain  (prosencephalon),  mid-brain  (mesencephalon),  and 
hind-brain  (rhombencephalon).  The  fore-brain  becomes  differ- 
entiated later  into  the  telencephalon  and  diencephalon ;  and  the 
hind-brain  likewise  is  differentiated  into  two  parts :  the  meten- 
cephalon  and  the  myelencephalon. 

From  these  brain-vesicles  are  developed  the  following: — 


Brain  or 
Encephalon, 


Rhomben- 
cephalon,  or 
hind-brain, 


Mesen- 
cephalon,  or 
mid-brain, 


'Myelenceph- 
alon, 


Metenceph- 
alon. 


(Medulla   oblongata, 
Lower   part  of   fourth 
ventricle. 

f  Cerebellum, 
j  Pons    Varolii, 
i  Upper  part  of  fourth 

j       ventricle. 


Isthmus  rhom-  ~) 

bencephali        ]  s         ior  cerebellar  pe- 
( narrow  part  ■ 


connecting 
with  mesen- 
cephalon 


y     duncles, 


Valve   of   Vieussens. 


>>       J 


{Mesenceph- 
alon, or  mid- 
brain, 


{Corpora  quadrigemina, 
Crura   cerebri, 
Aqueduct  of  Sylvius. 


THE  NERVOUS  SYSTEM. 


299 


Brain  or 
Encephalon. 
[continued  i 


Prosen- 
cephalon, 
fore-brain 


Thalamanceph- 
alon,  or  dien- 
cephalon, 


or  J 


Optic  thalami, 
Subthalamic   regions, 
Pituitary    and    pineal 

bodies. 
Structures   in  interpe- 
duncular  space. 
Optic  nerve  and  retina. 
Hinder    part   of    third 
ventricle. 


Cerebral    hemispheres, 
Olfactory   lobes, 
Lateral    ventricles, 
Telencephalon     <  Foramina  of  Monro, 
j  Anterior     portion     of 
i       third  ventricle. 


The  medulla  oblongata  (myelencephalon)  is  the  upper 
expanded  portion  of  the  spinal  cord,  extending  between  the 
lower  border  of  the  pons  and  the  upper  border  of  the  atlas.  It 
is  divided  by  two  fissures — the  anterior  (fissura  mediana  ante- 
rior) and  posterior  median  (fissura  mediana  posterior)  fissures 
— into  two  halves,  each  one  of  which  is  subdivided  into  four 
columns,  from  before  backward,  the  following: — 

(a)  Anterior  pyramids  (pyramis  medulla?  oblongata') ,  or 
corpora  pyramidalia,  are  two  pyramidal  masses  of  white  nervous 
matter,  placed  between  the  anterior  median  fissure  and  the 
olivary  body,  and  continuous  with  the  anterior  columns  of  the 
cord  below ; 

(b)  Lateral  tract  and  olivary  body,  are  continuous  with 
the  lateral  columns  of  the  cord  below; 

(c)  Eestiform  bodies  (corpus  restiforme)  are  continuous 
below  with  the  posterior  columns  of  the  cord.  They  are  com- 
posed of  the  fibers  of  the  columns  of  Goll  and  Burdach  and  the 
direct  cerebellar  tract.  They  diverge,  the  interval  between  them 
being  the  lower  portion  of  the  fourth  ventricle. 

The  structure  of  the  medulla  oblongata  consists  of  both 
white  and  gray  matter,  the  former  arranged  into  four  columns, 
the  latter  contained  in  the  interior. 

The  gray  matter  of  the  medulla  is  partly  arranged  into 
-  and  partly  continuous  with  the  gray  matter  of  the  cord. 
The  posterior  horns  are  called  here  "the  tubercles  of  Rolando" 
(tuberculum  Eolandi).  On  the  floor  of  the  fourth  ventricle 
{fo<sa  rhomboidea)  the  ganglion-cells  are  arranged  into  nuclei, 
from  which  several  of  the  cranial  nerves  have  their  origin. 


300 


HUMAN   ANATOMY. 


The  Pons  Varolii  connects  the  cerebrum  above  with  the 
cerebellum  behind  and  the  medulla  oblongata  below.  On  its 
under  surface  it  presents  a  groove    (sulcus  basilaris)    for  the 


Oan. 


Op.ch 

Suits-  iri'b 

Bk  I-P.C. 


a 


V,mfty    y-l^ 


Fig.  105. 

Surface  anatomy  of  the  niyelencephalon.  Roman  numerals  refer 
to  cranial  nerves.)  C.  1,  first  cervical  spinal  nerve;  C.  mam,  corpus 
mammillare;  Op.  n.,  optic  nerve;  Inf.,  infundibulum;  Op.  ch.,  optic 
chiasm;  Subs,  int.,  substantia  interpeduncugeniculate  body;  Sub.  b., 
basilar  sulcus;  M.  p.  c,  middle  peduncle  of  cerebellum;  F.,  flocculus; 
F.  h.,  horizontal  fissure;  0.,  olive;  T.  I.  s.,  ventrolateral  sulcus;  Pyr., 
pyramid;  V.  m.  f.,  ventral  median  fissure.  (Whitehead,  after  Van 
Qehuchten.) 


passage  of  the  basilar  artery.  The  upper  surface  forms  a  por- 
tion of  the  floor  of  the  fourth  ventricle  (fossa  rhomb oidea) ,  and 
on  either  side,  under  the  name  of  the  crus,  passes,  to  the  cere- 
bellum, forming  its  middle  peduncle  (brachia  pontis). 


THE    NERVOUS    SYSTEM. 


301 


CEREBELLUM. 

The  cerebellum,  ot  little  brain,  occupies  the  inferior  occip- 
ital fossae  beneath  the  great  cerebral   Lobes,  from  which   it   is 

separated  by  the  tentorium.  Its  average  weight  is  a  little  over 
five  ounces  in  the  male,  and  is  proportioned  to  the  greater  brain 
about  one  to  twenty.  It  is  oblong,  flattened  from  above  down- 
ward, and  divided  into  two  lateral  hemispheres  connected  by  a 
central  portion,  the  vermiform  process  (vermis). 

It  is  composed  of  gray  and  white  matter — the  former  upon 
the  surface.  It  is  not  convoluted,  like  the  cerebrum,  but  con- 
>i>t>  of  a  number  of  thin  plates,  folia,  arranged  in  a  series  of 
crescent ic  curves,  with  the  concavity  forward. 

The  cerebellum  consists  of  a  central  lobe  (vermis),  and 
two  lateral  hemispheres  (Itemisphcrria  cerebelli).  The  latter 
are  separated  on  the  inferior  surface  of  the  cerebellum  by  a 
deep  hollow,  the  valley  or  vallecula  (vallecula,  cerebelli),  which 
Lodges  the  medulla  oblongata.  The  floor  of  the  vallecula  is 
formed  by  the  inferior  portion  of  the  vermis. 

The  incisura  semilunaris  (incisura  cerebelli  anterior)  sep- 
arates the  hemispheres  in  front,  and  rests  against  the  corpora 
quadrigemina; 

The  incisura  marsupialis  (incisura  cerebelli  jiostrrior) 
separates  the  hemispheres  behind,  and  receives  the  upper  por- 
tion of  the  falx  cerebelli ; 

The  great  horizontal  fissure  (sulcus  horizontalis  cerebelli) 
separates  the  cerebellum  into  a  superior  and  an  inferior  surface. 

The  upper  surface  (fades  cerebelli  superior)  shows  the 
superior  vermis  (vermis  superior  cerebelli),  with  its  correspond- 
ing Lobes  in  the  hemispheres.  These  latter  are  separated  from 
each  other  by  fissures.  The  following  table  gives  the  arrange- 
ment of  the  lobules : — 


G 

beat  Horizontal 

ElSSIRE. 

Pre- 

Frsenulum 

Lingula. 

Frsenulum 

central  fissure 

Post- 

Ala. 

rJbbus  cenl  ral  is. 

Ala. 

Anterior 

Anterior 

crescentic 

Lobus  culminis. 

crescent  ic 

I'n- 

lobe. 

lobe. 

Posterior 

Posterior 

crescent  i(- 

Lobus  cljvi. 

crescenl  ic 

lobe. 

lobe. 

I'o-I 

Posterior 

Posterior 

Great 

superior 
lobe 

Folium  cacuminis. 

superior 
lobe. 

horizontal 
fissure. 

302 


HUMAN    ANATOMY. 


The  inferior  surface  (fades  cerebelli  inferior)  of  the  cere- 
bellum presents  the  deep  depression,  the  vallecula,  which  ren- 
ders the  connection  between  the  vermis  and  the  hemispheres 
less  intimate.  The  divisions  of  the  vermis  and  their  correspond- 
ing lobules  in  the  hemispheres  are  as  follows : — 


Great 


Post- 


Pre- 


Post- 


Great 


Slender  lobe, 
post-gracile, 
posterior  in- 
ferior  lobule. 


Lobulus 
biventer. 


Amygdala. 


Flocculus. 


Tuber     valvulse 


Pyramis. 


Uvula. 


Nodule. 


Posterior 
inferior 
lobule. 


Lobulus 
biventer. 


Amygdala. 


Flocculus. 


horizontal 
fissure. 


pyramidal 
fissure. 


pyramidal 
fissure. 

nodular 
fissure. 


horizontal 
fissure. 


The  cerebellum  is  connected  with  the  encephalon  by  the 
peduncles  of  the  cerebellum,,  three  in  number,  from  above  down- 
ward, as  follows : — 

Crura  ad  cerebrum,  superior  cerebellar,  peduncles,  or 
processus  e  cerebello  ad  testes  (bracliia  conjunctiva  cerebelli), 
pass  to  the  cerebrum ; 

Crura  ad  posterior,  middle  cerebellar  peduncles,  or  proces- 
sus ad  pontem  (bracliia  pontis),  the  transverse  fibers  of  the  pons 
Varolii,  connect  the  hemispheres; 

Crura  ad  medullam,  inferior  cerebellar  peduncles  or  proces- 
sus e  cerebello  ad  medullam,  the  restiform  bodies  of  the  medulla 
oblongata  (corpora  restiformia),  connect  with  medulla  ob- 
longata. 

.  The  internal  structure  of  the  cerebellum  consists  of  an 
arbor  vitge  arrangement  of  gray  matter,  inclosing  a  white  mass. 
In  center  of  the  latter  is  found  a  grayish,  dentated  mass,  the 
corpus  dentatum  (nucleus  dentatus),  an  irregular  capsule  of 
gray  matter  opening  anteriorly. 


TITE     CEREBRUM 


consists  of  a  large,  ovoidal  mass,  divided  into  two  lateral  halves, 
or  hemispheres  (hemisphmria  cerebri),  by  the  great  longitudinal 


THE    NERVOUS    SYSTEM. 


303 


fissure  (fissura  longitudinalis  cerebri),  connected  by  a  white 
Transverse  commissure — the  corpus  callosum.  The  surface  is 
irregularly  marked  by  convolutions,  or  gyri  (gyri  cerebri), 
separated  from  each  other  by  irregular  depressions,  fissures 
( tis.<nru) .  or  sulci  (sulci  cerebri).  The  outer  surface  is  com- 
posed of  gray  matter,  which,  from  its  location,  is  called  the 
cortical  substance.     The  interior  surface,  for  the  most  part,  is 


white. 


&?<■■  J/t.    J.poste, 


S.ieft/p 


Lift  side  of  human  cerebrum.  »S'.  fr.  s.,  superior  frontal  sulcus; 
8.  prase,  precentral  sulcus;  8.  R.,  central  sulcus  of  Rolando;  8.  poste., 
Post-central   sulcus;    8.    Interp.,   interparietal  sulcus;   8.   p.   o.,  parieto- 

i  ItaJ  fissun  :  Hunt.  post.  8.,  posU  rior  ramus  of  fissure  of  Sylvius; 
8.  temp.  in.,  middle  temporal  sulcus;  8.  temp.  8.,  superior  temporal 
sulcus;  /•'.  8.,  fissure  of  Sylvius;  R.  ant.  08C.  8.,  ascending  anterior 
ramus  of  fissure  of  Sylvius;  R.  s.  h.  8.,  horizontal  anterior  ramus  of 
fissure  of  Sylvius;  8.  fr.  inf.,  inferior  frontal  sulcus.  (Whitehead, 
after   Van  Oehuchten.) 

The  principal  fissures  of  the  brain  are  five,  as  follows: — 

].  The  great  longitudinal  fissure  (fissura  longitudinalis  cerebri), 
separating  tin-  two  hemispheres  from  one  another. 

■>.  The  great  transverse  fissure  of  Bichal  (fissura  cerebri  trans- 
betweeen  the  cerebellum  mid  the  cerebrum,  admitting  the  pia 
mater  to  form  tin-  velum  interpositum. 

.;.  The  fissure  of  Sylvius  -fissura  cerebri  lateralis  [Sylvii]),  be- 
ginning  at  tin-  anterior  perforated  apace  and  ascending  obliquely. 


304  HUMAN    ANATOMY. 

4.  The  fissure  of  Rolando  {sulcus  centralis  [Rolandi]),  descends 
from  near  the  middle  of  the  great  longitudinal  fissure  to  join  the  fissure 
of  Sylvius. 

5.  The  parieto-occipital  fissure  {sulcus  occipitoparietalis) ,  on  the 
postero-Iateral  aspect  of  the  cerebrum. 

6.  The  callosomarginal  fissure   {sulcus  singulus) . 

7.  The  collateral   fissure    {fissura  collateralis) . 

8.  The  limiting  sulcus  of  Reil  (sulcus  circularis  [Reili]). 

The  principal  lobes  of  the  brain  are  six,  as  follows : — ■ 

1.  Frontal  lobe-  (lobus  frontalis) ,  on  the  outer  surface  of  the  brain; 
it  is  bounded  below  by  the  fissure  of  Sylvius,  and  behind  by  the  fissure 
of  Rolando.  On  the  mesial  surface  it  is  bounded  by  the  callosomarginal 
fissure,  and  on  the  inferior  surface  it  is  bounded  behind  by  the  stem  of 
the  Sylvian  fissure. 

On  the  outer  surface  it  is  divided  into  the 

(a)  Ascending     frontal     convolution      {gyrus     frontalis     as- 
cendens) ; 

(b)  Superior  frontal  convolution  (gyrus  frontalis  superior); 

(c)  Middle  frontal  convolution   (gyrus  frontalis  medius)  ; 

(d)  Inferior  frontal  convolution   (gyrus  frontalis  inferior)  ; 
On  the  mesial  surface  it  is  divided  into 

(a)  Marginal  gyrus    (gyrus  marginalis)  ; 

(b)  Paracentral   lobule    (lobulus  paracentralis) . 
On  the  orbital  surface  it  is  divided  into 

(a)  Internal  orbital  convolution   (gyrus  orbit alis  internus)  ; 

(b)  Anterior  orbital  convolution   (gyrus  orbitalis  anterior)  ; 

(c)  Posterior  orbital  convolution   (gyrus  orbitalis  posterior) . 

2.  Parietal  lobe  (lobus  parietalis) ,  lies  between  the  fissure  of 
Rolando,  the  parieto-occipital,  and  the  fissure  of  Sylvius,  and  consists 
of  five  gyri :  — 

(a)   Ascending      parietal       (gyrus 

centralis  posterior)  ; 
(6)    Superior      parietal       (lobulus 

parietalis  superior)  ;  f  Supra-marginal     (gyrus    supramar- 

(c)    Inferior       parietal        (lobulus  I        ginalis) , 

parietalis  inferior ) ,  '■   Angular    (gyrus  angularis), 

*-  Post  parietal; 

3.  Occipital  lobe  (lobus  occipitalis)  lies  at  the  posterior  aspect 
of  the  cerebrum  and  is  divided  into  first,  second  and  third  occipital 
convolutions. 

4.  Temporosphenoidal  lobe  or  temporal  lobe  (lobus  temporalis) , 
occupies  the  middle  fossa  of  the  skull. 

5.  Island  of  Reil,  or  central  lobe,  lies  within  the  fissure  of  Sylvius. 
It  consists  of  six  convolutions — the  gyri  operti. 

6.  The  limbic  lobe  surrounds  the  corpus  callosum.  Its  extremities 
are  united  by  the  roots  of  the  olfactory  tract. 

The  inner  or  median  surface  of  the  hemispheres  presents 
five  fissures,  as  follows : — 

1.  Callosomarginal    (sulcus  cingulus) . 

2.  Parieto-occipital   (sulcus  occipitoparietalis). 

3.  Calcarine   (fissura.  calcarina) . 

4.  Occipitotemporal  or  collateral    (fissura  collateralis) . 

5.  Dentate  fissure,  or  sulcus  hippocampi    (fissura  hippocampi). 


THE    NERVOUS    SYSTEM. 


305 


The  lobes  on  the   internal   surface  are  six   in   number,  as 

follows : — 

1.  Callosal    convolution    {gyrus  formcatus   or   gyrus   cinguli),   de- 
scends as  the  gyrus  hippocampi  and  terminates  as  the  uncinate  gyrus. 

•1.  Marginal   (gyrus  marginaUs),  or  first  frontal  convolutions. 

3.  Quadrate    (projcuneus) . 

4.  Cuneus,   or  occipital  lobule    (lobus  occipitalis). 

5.  Uncinate  gyrus. 

6.  Temporosphenoidal  lobe  or  temporal  lobe   (lobus  temporalis). 


Sul  C.C. 


Su?.ima>J- 


Sulsuhf' 


Sulsubp 


FlS.p-Q; 


..sSulcalmiy 


fis.  c&k. 


Fig.  107. 

Convolutions  and  ficsures  of  the  median  and  tentorial  surfaces  of 
the  right  cerebral  hemisphere.  Fis.  8.,  fissure  of  Sylvius;  Sul.  cat. 
marg.,  callosomarginal  sulcus;  Sul.  subf.,  subfrontal  sulcus;  Sul.  C.  0., 
sulcus  of  corpus  callosum;  Sul.  marg.,  marginal  sulcus;  Sul.  subp., 
subparietal  sulcus;  Fis.  p.  o.,  parieto-occipital  fissure:  Fie.  calc,  cal- 
carine  Bssure;  Fis.  den.,  dentate  Assure;  Fis.  col.,  collateral  fissure. 
{Whitehead,  after  Van  Qehuchten.) 

The  inferior  surface  (fades  basalis  encephali)  of  each. 
hemisphere  lb  divided  into  three  lobes — the  anterior,  middle 
and  posterior.  The  two  former  occupy  the  anterior  and  middle 
fossa  of  the  skull  and  the  posterior  rests  upon  the  cerebellum, 
separated  from  it  by  the  tentorium.  This  surface  presents  for 
study  from  before  backward  the  following  points: — 

The  longitudinal  fissure  (fissura  longitudinalis  cerebri),  separates 
the  two  hemispheres; 

Corpus  calloan in.  the  great  transverse  commissure  of  the  cerebrum, 
extending  bj  means  of  its  peduncles  to  near  the  Sylvian  fissure; 

20 


306  HUMAN    ANATOMY. 

[Aim ina  eincrca.  is  ;\  thin,  gray  layer,  forming  the  anterior  part  of 
the  inferior  boundary  of  the  third  ventricle: 

Olfactory  nerve,  with  it*  bulb; 

Fissure  of  Sylvius  [fissura  cerebri  lateralis  [Sylvii]),  between  the 
anterior  and  middle  lobes  of  the  cerebrum,  and  lodges  the  middle  cere- 
bral artery: 

Anterior  perforated  space  (locus  perforatus  anticus  or  substantia 
perforata  anterior),  transmits  vessels  to  the  corpus  striatum: 

Optic  commissure  [chiasma  optieum).  is  formed  by  the  junction  of 
the  optic  tracts; 

Tuber  cinaeutn.  is  a  gray  eminence  between  the  corpora  albicantia 
and  optic  tracts,  and  forms  part  of  the  tloor  of  the  third  ventricle: 

Infiindibuluni,  is  a  tube  of  gray  matter  connecting  the  pituitary 
body  with  the  third  ventricle: 

Pituitary  body  {hypopht/sis  cerebri),  is  a  small,  vascular,  bilobed 
body,  connected  by  the  infundibulum  and  occupying  the  sella  turcica 
(for  histology   vide  '•Ductless  Glands"); 

Corpora  albicantia.  or  mammillaria.  are  two  white,  rounded 
masses,  formed  by  the  folding  of  the  anterior  crura  of  the  fornix,  and 
are  sometimes  called  the  bulbs  of  the  fornix: 

Posterior  perforated  space  [locus  perforatus  posticus:  or  sub- 
stantia perforata  posterior) .  allows  the  passage  of  blood-vessels  to  the 
optic  thalami; 

Crura  cerebri  (pedunculi  cerebri),  or  cerebral  peduncles,  connect 
the  cerebrum  with  the  medulla,  cerebellum,  and  spinal  cord:  they  con- 
sist of  the  anterior  portion,  or  crusta.  and  the  posterior  portion,  or 
tegmentum,  between  which  is  a  mass  of  gray  matter — the  locus   niger: 

Pons  Varolii,  covers  up  the  posterior  portion  of  the  cerebral  lobes. 

Interior  of  the  Cerebrum. — The  interior  of  the  cere- 
brum, viewed  above  the  level  of  the  corpus  eallosum.  presents 
a  white  surface — the  centrum  ovale  minus,  the  margins  of 
which  are  convoluted  gray  matter,  and  are  called  labia  cerebri. 
It  is  studded  throughout  with  minute  blood  vessels — puncta 
vaseulosa. 

The  hemispheres,  viewed  on  a  level  with  the  corpus  eallo- 
sum. present  a  large  white  mass — the  centrum  ovale  majus — in 
the  center  of  which  is  the  connecting  band,  the  corpus  eallosum. 

Corpus  Calhmim. — This  connecting  band  forms  the  roof 
of  the  lateral  ventricles.  It  is  about  four  inches  in  length  and 
varies  from  an  inch  and  a  halt'  to  two  inches  in  width,  present- 
ing in  front  a  bend,  or  genu  (genu  corporis  caUosi).  below 
which  it  terminates  in  the  tuber  einereum  through  the  lamina 
cinerea. 

Posteriorly  it  forms  a  thick,  rounded  fold — the  splenium 
(spleniutn  corporis  caUosi).  or  pad — which  is  continuous  with 
the  fornix. 

The  peduncles  of  the  corpus  eallosum  ( gyrus  subcallosus  or 
peduncular  corporis  caUosi)  are  two  reflected  bundles  of  white 
matter  given  off  near  the  anterior  termination  of  the  corpus, 


THE    NERVOUS    SYSTEM. 


307 


and    each    passing    backward    across    the    anterior    perforated 
space  of  its  own  side  to  the  fissure  of  Sylvius. 

The  superior  surface  of  the  corpus  callosum   shows  a  de- 


Julfitf. 


Fig.  108. 

Inferior  aspect  of  cerebral  hemisphrro.  Bui.  <>lf.,  olfactory  sulcus; 
Bui.  tim/i.  inf..  Inferior  temporal  sulcus;  Fis.  col.,  collateral  fissure. 
{Whitehead,  after  \'<m  Oehuchten  | 


pression — tlie  raphe — bounded  <>u  each  Bide  by  elevated  bands, 
the  stria  longitudinales,  or  nerve-  of  Lancisi.  Externa]  to  these 
are  the  stria   longitudinaJes  laterales.     On  either  side  of  the 


308  HUMAN    ANATOMY. 

raphe  are  many  transverse  lines — the  linear  transversa?,  which 
indicate  the  direction  of  the  fibers  of  the  corpus. 

The  cerebral  commissuees  are  connecting  bands  of  gray 
and  white  matter,  pursuing  either  a  transverse  or  anteroposte- 
rior course. 

Transverse: — 

Anterior  (commissura  anterior  cerebri),  middle,  gray,  or  soft  com- 
missure (massa  intermedia  or  commissura  mollis),  and  posterior  com- 
missure ; 

Corpus  callosum; 

Optic  chiasm    (chiasma  opticum)  ; 

Fornix ; 

Pons  Varolii; 

Posterior  medullary  velum   (velum  medullare  posterius). 

A  n  tero  posterior : — 

Corpus  callosum   (nerves  of  Lancisi)  ; 

Fornix ; 

Fasciculus  uncinatus    (uncinate  fasciculus)  ; 

Taenia  semicircularis    (stria?  terminalis)  ; 

Callosal  convolution    (gyrus  fornicatus)  ; 

Inferior  longitudinal  fasciculus  (fasciculus  longitudinalis  inferior)  ; 

Olfactory  tracts    (tractus  olfactorius)  ; 

Crura  cerebri    (pedunculi  cerebri)  ; 

Peduncles  of  pineal  gland   (habenula)  ; 

Processus  e  cerebello  ad  testes. 

VENTRICLES    OF    THE    BRAIN. 

The  interior  of  the  brain  contains  .  five  distinct  cavities, 
named  the  ventricles  of  the  brain,  situated  as  follows:  Two  lat- 
eral ventricles  (ventriculus  lateralis),  in  the  upper  part,  within 
the  substance  of  the  hemispheres,  the  third  ventricle  (ventriculus 
tertius)  between  the  optic  thalami  at  the  base  of  the  brain,  the 
fourth  ventricle  (ventriculus  quartus)  between  the  medulla 
oblongata  and  the  cerebellum,  and  the  fifth  ventricle  within  the 
septum  lucidum  between  the  two  lateral  ventricles. 

The  ventricles  intercommunicate — the  two  lateral  ventricles 
with  the  third  by  means  of  the  foramen  of  Monro  (foramen 
interventriculars) ,  the  third  with  the  fourth  ventricle  by  means 
of  the  iter  a  tertio  ad  quartum  ventriculum  (aquceductus  cere- 
bri), and,  in  the  fetus,  with  the  fifth,  and  through  the  infundib- 
ulum  with  the  cavity  of  the  pituitary  body. 

The  lateral  ventricle  (ventrv  ulus  lateralis)  is  bounded 
as  follows : — 

The  roof,  the  corpus  callosum;  the  floor  is  formed  by  the  follow- 
ing  parts    from   before   backward:     corpus    striatum,    taenia    semicircu- 


THE    NERVOUS    SYSTEM. 


309 


laris.  optic  thalamus,  choroid  plexus,  corpus  fimbriatum  and  fornix; 
internally,  by  tlie  septum  lucidum;  externally,  in  front  and  behind  by 
the  brain-substance.  Each  lateral  ventricle  presents  three  cornua — the 
anterior  cornu,  posterior  cornu,  or  digital  comity,  and  the  middle  count. 


—-Antlcorr 
Nud cauef 


ton 


_— Post.  cor. 


Fig.  109. 

The  lateral  ventricles  and  choroid  plexus.  St.  term.,  stria  termin- 
als; That.,  thalamus;  Hipp.,  hippocampus;  Fimb.,  fimbria;  .1;//  cor 
anterior  cornu  of  lateral  ventricle;  Nucl.  caud.,  nucleus  caudatus;  Col. 
for.,  columns  of  the  fornix;  Yd.  int.,  velum  interpositum;  Ch.  pi., 
choroid  plexus;  Cat  wo.,  calcar  avis;  Post,  cor.,  posterior  cornu  of 
lateral    ventricle    [Whitehead,    after   '/ray.) 

The  anterior  cornu  (cornu  anterius)  curves  outward  and 
forward  over  the  corpus  striatum  and  into  the  anterior  lobe. 

The  middle  cornu  (cornu  inferius)  passes  into  the  middle 
lobe,  descending  to  the  transverse  fissure  at  the  base  of  the  brain. 


310  HUMAN    ANATOMY. 

Its  course  is  backward',  outward,  downward,  forward  and  inward 
(B.,  0.,  D.,  F.,  I.). 

The  posterior  cornu  (cornu  posterius)  runs  backward  into 
the  posterior  lobe,  its  course  being  backward,  outward  and 
inward  (B.,  0.,  I.). 

Parts  of  Lateral  Ventricle — Corpus  Callosum. — Described 
above. 

Septum  Lucidum  (septum  p el 'lucid him) . — Forms  the  inter- 
nal boundary  of  the  lateral  ventricle.  It  consists  of  two  layers 
of  white  and  gray  matter,  and  is  attached  above  to  the  under 
surface  of  the  corpus  callosum.  below  to  the  fornix,  and  ante- 
riorly  to  the  prolongation  of  the  corpus  callosum. 

Between  the  laminae  forming  the  septum  is  a  narrow  inter- 
val— the  fifth  ventricle. 

The  Corpus  Striatum. — Situated  in  the  lateral  ventricle, 
its  broad  end  directed  forward  into  the  fore  part  of  the  body 
and  anterior  cornu  of  the  ventricle,  its  narrow  end  directed 
outward  and  backward,  and  separated  from  its  fellow  by  the 
thalami  optici. 

The  intraventricular  portion  is  called  the  caudate  nucleus 
(nucleus  caudatus),  the  extraventricular,  the  lenticular  nucleus 
(nucleus  lentiformis) ,  the  two  separated  by  the  internal  capsule. 

The  internal  capsule  (capsula  interna)  is  a  large  layer  of 
white  fibers,  derived  from  the  medulla  and  crura  cerebri,  sep- 
arating the  lenticular  nucleus  from  the  caudate  nucleus  ante- 
riorly, and  the  lenticular  nucleus  from  the  optic  thalamus 
posteriorly. 

The  external  capsule  (capsula  externa)  is  a  small  layer  of 
white  fibers  on  the  outer  surface  of  the  corpus  striatum,  between 
the  lenticular  nucleus  and  the  claustrum. 

The  claustrum  is  a  convoluted  layer  of  gray  fibers  between 
the  external  capsule  and  the  island  of  Reil. 

The  Tcenia  Semicircular  is,  or  Horny  Band  of  Tarinus 
stria  terminalis). — A  band  of  medullary  substance  in  the  fur- 
row between  the  corpus  striatum  and  the  optic  thalamus.  Its 
anterior  portion  descends  with  the  anterior  pillar  of  the  fornix, 
its  posterior  portion  passes  into  the  descending  horn.  Beneath 
it  is  the  vena  corporis  striati. 

The  choroid  plexus  (plexus  chorioideus) ,  a  vascular  mem- 
brane, occupying  the  margin  of  a  fold  of  pia  mater,  known  as 
the  velum  interpositum  (tela  chorioidea  superior;  or,  tela 
chorioidea  ventriculi  tertii) .  It  runs  across  the  floor  of  the 
lateral  ventricle,  and  communicates  with  its  fellow  of  the  op- 


THE    NERVOUS    SYSTEM.  3-Q 

polite   side   through    the   foramen    of    Monro.      Posteriorly    it 

descends  into  the  middle  horn  of  the  lateral  ventricle. 

The  corpus  iimbriatum  (tcenia  hippocampi  or  tamia  fim- 
bria), a  narrow  white  hand  behind  the  choroid  plexus.  It  is 
the  lateral  edge  of  the  posterior  pillar  of  the  fornix. 

The  fornix,  a  lamella  of  white  tibrous  matter,  beneath  the 
corpus  eallosum,  continuous  with  it  posteriorly,  but  separated 
from  it  anteriorly  by  the  septum  lucidum.  It  consists  of  two 
symmetrical  halves  which  join  to  form  the  body  (corpus  forni- 
cis),  each  half  having  an  anterior  and  posterior  crus  where  they 
do  not  join. 

The  anterior  crura  (columnar  fornicis)  curve  down  to  the 
base  of  the  brain,  where  each  crus  spreads  out  and  curves  upon 
itself  to  form  the  corpus  albicans  of  that  side.  From  this  point 
it  passes  to  the  corresponding  optic  thalamus. 

The  posterior  crura  (crura  fornicis),  at  their  commence- 
ment, are  joined  to  the  under  surface  of  the  corpus  eallosum. 
They  pass  downward  into  the  descending  horns  of  the  lateral 
ventricles,  being  continuous  with  the  concave  borders  of  the 
hippocampi  majores. 

The  lateral  edge  of  the  posterior  crus  is  called  the  corpus 
fimbriatum. 

The  lyra  is  a  series  of  lines,  some  transverse,  others  longi- 
tudinal and  oblique,  on  the  under  surface  of  the  fornix,  between 
the  diverging  posterior  crura. 

Optic  Thalamus  (thalamus). — The  thalami  optici  are  two 
large  ganglionic  masses,  situated  between  the  diverging  portions 
of  the  corpora  striata.  Each  thalamus  rests  upon  the  eorre- 
sponding  crus  cerebri. 

The  thalamus  is  bounded  externally  by  the  corpus  striatum 
and  taenia  semicircularis.  and  internally  forms  the  lateral 
boundary  of  the  third  ventricle. 

Its  upper  surface  is  partly  covered  by  the  fornix.  Its 
under  surface  forms  the  roof  of  the  descending  horn  of  the 
lateral  ventricle. 

It-  posterior  and  inferior  part  exhibits  two  rounded  emi- 
nences, the  external  (corpus  geniculatum  hiferale)  and  internal 
(corpus  geniculatum  mediate)  geniculate  bodies.  Its  anterior 
extremity  form-  the  posterior  boundary  of  the  foramen  of 
Monro,  which  foramen  connects  the  two  lateral  ventricles  with 

the  third. 

Velum  interpositiini  (tela  chorioidea  ventriculi  tertii),  a 
vascular  membrane,  reflected  from  the  pia  mater  into  the  inte- 
rior  of   the   brain    through   the  transverse    fissure.      It   passes 


312  HUMAN    ANATOMY. 

beneath  the  posterior  border  of  the  corpus  callosum  and  fornix, 
and  above  the  corpora  quadrigemina,  the  pineal  gland  and  the 
optic  thalami.  It  forms  the  roof  of  the  third  ventricle  (plexus 
chorioidea  ventriculi  tertii).  Its  anterior  extremity  passes  on 
each  side  into  the  corresponding  lateral  ventricle,  forming  the 
anterior  extremity  of  the  choroid  plexus.  The  vascular  fringes 
of  the  velum  interpositum  projecting  into  the  third  ventricle 
are  called  the  choroid  plexuses  of  the  third  ventricle. 

It  has  two  veins,  the  venae  G-aleni  (w.  cerebri  internee), 
which  run  along  its  under  surface  and  are  formed  by  the  veins 
of  the  choroid  plexuses  and  the  vena?  corporis  striata  (v.  cor- 
poris striata).  The  venge  Galeni  unite  to  form  a  single  trunk 
■ — vena  magna  Galeni — (v.  cerebri  magna)  and  empty  into  the 
straight  sinus. 

The  posterior  cornu  (cornu  postering)  of  the  lateral  ven- 
tricle runs  into  the  substance  of  the  posterior  lobe.  On  the  floor 
of  this  horn  is  an  eminence  corresponding  to  a  sulcus  be- 
tween two  convolutions,  and  called  the  hippocampus  minor 
(calcar  avis). 

Between  the  posterior  and  middle  (cornu  inferius)  horns  is 
another  eminence — the  eminentia  collateralis,  or  pes  accessorius. 

The  hippocampus  major,  or  cornu  ammonis  (hippocam- 
pus), a  white  eminence  running  the  entire  length  of  the  floor 
of  the  middle  horn.  This  eminence  is  the  doubled-in  surface 
of  the  gyrus  fornicatus. 

The  lower  extremity  of  the  hippocampus  major  is  called 
the  pes  hippocampus  (digitationes  hippocampi). 

The  fascia  dentata  (fascia  dentata  hippocampi) ,  the  gray 
and  serrated  edge  of  the  middle  lobe.  It  is  really  external  to 
the  cavity  of  the  middle  cornu. 

The  third  ventricle  (ventriciilus  tertius)  is  a  mere 
fissure  in  the  median  line  of  the  cerebrum,  situated  between 
the  optic  thalami.  It  communicates  with  the  lateral  ventricle 
by  the  foramen  of  Monro  and  with  the  fourth  ventricle  by  the 
iter  a  tertio  ad  quartum  ventriculum.  The  cavity  is  crossed  by 
three  commissures — the  anterior  commissure,  a  white,  rounded 
cord ;  the  middle  or  soft  commissure,  composed  of  gray  matter ; 
and  the  posterior  commissure,  a  white  band  connecting  the  two 
optic  thalami.     It  is  bounded  by  the  following  structures : — 

The  roof,  by  the  velum  interpositum,  suspending  the  choroid  plex- 
uses of  the  third  ventricle,  and  laterally  the  peduncles  of  the  pineal 
gland;  floor,  by  the  parts  inclosing  the  interpeduncular  space  at  the 
base  of  the  brain,  viz. :  the  lamina  cinerea,  tuber  einereum  and  infundib- 
ulum,  corpora  albican tia  and  the  posterior  perforated  space;   laterally, 


THE    NERVOUS    SYSTEM. 


313 


by  the  optic  tlialami;  m  front,  by  the  anterior  commissure  and  anterior 
crura  of  the  fornix;  behind,  the  posterior  commissure  and  the  iter  a 
tertio  ad  quartum  ventricuhun. 

The  fourth  vextricle  (ventriculus  quartus)  is  a  dia- 
mond-shaped cavity  between  the  cerebellum  behind  and  the 
posterior  surface  of  the  medulla  oblongata  and  pons  in  front. 
It  is  inclosed  behind  by  the  pia  mater,  which  contains  an  open- 
ing for  the  exit  and  entrance  of  the  subarachnoid  fluid  from 
the  subarachnoidean  space  of  the  brain  and  spinal  cord,  and 
a  vascular  fold  of  pia  mater — the  choroid  plexus.     Its  lower 


Ch.ro  i  J 

/Pineil    Stria 
?^L          /Kntal  R«tess   of  W  Vent. 

P'swA^, ■ 

I^IIS^ 

\ v? 

\W  SM/           \"Su-P     Clorp     <^M.aJ. 

&-'t«ofR«f:P„f  Space- 

^••WjNV            J 

"**"""— AF-Wexty- 

FIG.  110. 

Mesial  section  of  brain  and  brain  stem.  1,  anterior  commissure; 
2,  middle  commissure;  3,  posterior  commissure;  4,  pituitary  body; 
IV,   fourth  ventricle. 


angle  is  continuous  with  tbe  central  canal  of  the  spinal  cord; 
and  from  the  resemblance  it  bears  to  a  writing-pen,  the  name 
calamus  scHptorvus  is  applied.  It  communicates  in  front  with 
the  tbird  ventricle  by  tbe  iter  a  tertio  ad  quartum  ventriculum. 
It  is  bounded  as  follows: — 

Tin-  roof,  valve  of  Vieussens  (rchun  mrihilhirr  antrrius)  and  the 
cerebellum,  containing  in  front  the  foramen  of  Magendie  [apertura 
medialia  ventricuM  quorti),  by  which  it  communicates  with  the  sub- 
arachnoidean  -pace:  the  floor,  of  rhomboidal  outline,  is  traversed  by  a 
vertical  median  fissure  [sulcus  longitudinalis  fossce  rhomboidece)  con- 
tinuous with  the  central  canal  of  the  cord.  At  the  broadest  part  of  the 
ventricle  are  a    series  of   transverse  white   lines  or   stria'   medullares,   de 


314  HUMAN   ANATOMY. 

rived  from  the  cochlear  root  and  nucleus.  These  striae  divide  the  floor 
into  two  triangles,  a  superior  and  an  inferior.  The  inferior  triangle 
presents  a  groove,  the  fovea  inferior,  whose  diverging  limbs  below  form 
the  so-called  ala  clnerea,  which  is  a  darker  colored,  triangular  space. 
There  are  in  this  locality  several  eminences,  corresponding  with  the 
nuclei  of  origin  of  the  pneumogastric,  glossopharyngeal  and  other 
cranial  nerves.  The  superior  triangle  presents  an  elevation,  produced  by 
underlying  white  fibers,  the  fasiculus  teres  (colUculus  facialis).  Above 
and  external  to  the  fasciculus  teres  is  a  depression,  the  fovea  superior; 
and  just  above  this  is  a  bluish  area,  the  locus  ccc-ruleus.  This  mottled 
appearance  is  caused  by  the  presence  of  the  substantia  ferruginea,  a 
peculiar  pigment  of  some  of  the  nerve  cells  and  in  them,  one  of  the  roots 
of  the  trifacial  nerve  terminates.  Anteriorly,  the  pons  Varolii  and 
medulla  oblongata;  posteriorly,  the  cerebellum;  laterally,  the  processus 
e  cerebello  ad  testes,  the  restiform  bodies,  and  posterior  pyramids  of 
the  medulla. 

Its  lining  membrane  is  continuous  with  that  of  the  third 
ventricle. 

The  fifth  ventricle  (cavtim  septi  pellucidi)  is  a  narrow 
fissure,  formed  within  the  two  lamince  of  the  septum  lucidum, 
being  originally  a  part  of  the  great  longitudinal  fissure.  It  is 
bounded : — 

Above,  by  the  under  surface  of  the  corpus  callosum; 
Below,  by  the  anterior  part  of  the  fornix; 

Laterally,  by  the  lateral  ventricles,  from  which  it  is  separated  by 
the  septum  lucidum. 

It  is  not  lined  with  epithelium. 

The  mesencephalon  includes  those  portions  of  the  brain 
substance  which  connect  the  cerebrum,  cerebellum  and  medulla 
oblongata  together,  and  comprises  the  following  structures : — 

Crura  cerebri,  before  described  (ante,  p.  306). 

The  valve  of  Vieussens,  or  anterior  medullary  velum,  is  a 
thin  layer  of  white  matter  stretched  between  the  processes  e 
cerebello  ad  testes,  and  forming  the  roof  of  the  iter  a  tertio  ad 
quartum  ventriculum.  It  presents  an  elevated  ridge  descend- 
ing on  its  upper  part  from  '  the  corpora  quadrigemina — the 
frenulum. 

Corpora  or  tubercula  quadrigemina,  or  optic  lobes,  are  four 
spherical  eminences,  placed  in  pairs  above  the  valve  of  Vieus- 
sens, and  behind  the  third  ventricle,  beneath  the  posterior  bor- 
der of  the  corpus  callosum. 

The  two  anterior  are  called  the  nates  (colliculi  superiores) , 
the  two  posterior  the  testes  (colliculi  inferiores).  The  brachia 
anterior — (brachium  quadrigeminum  superius)  and  posterior — 
brachium   quadrigeminum  inferius)    are  two  white  cords  con- 


THE  NERVOUS  SYSTEM.  315 

iiecting  them  with  the  optic  thalamus   and  beginning  of  the 
optic  Bracts. 

The  processus  e  cerebello  ad  testes  connect  them  with  the 
cerebellum. 

To  the  outer  side  of  the  optic  lobes  are  two  small  masses 
called  the  corpus  geniculatum  externum  (corpus  genie  id  atum 
Jul  crate)  and  internum  (corpus  geniculatum  mediate). 

The  pineal  gland,  or  epiphysis  cerebri  (corpus  pineale),  is 
a  >mall  reddish,  conical  body,  resting  upon  and  between  the 
nates.  It  represents  the  rudiment  of  a  median  eye  of  certain 
extinct  lizards  and  amphibia  (Spencer).  It  is  attached  to  the 
cerebrum  by  its  two  peduncles  (habenula),  and  is  held  in  posi- 
tion by  a  fold  of  the  pia  mater.  It  contains  a  cavity,  tilled  with 
a  viscid  fluid  and  secretory  matter  composed  of  phosphate  and 
carbonate  of  lime,  phosphate  of  magnesia,  ammonia,  and  a  little 
animal  matter — -the  acervulus  cerebri. 

THE    INTERNAL    STRUCTURE    OF    THE    MEDULLA    OBLONGATA. 

The  anterior  and  lateral  pyramidal  tracts  of  the  cord  are 
continued  into  the  medulla  oblongata  as  the  pyramids.  The 
lateral  pyramidal  tracts  decussate  in  the  lower  part  of  the 
medulla. 

The  anterior  ground  bundle  is  continued  upward  into  the 
medulla  as  the  posterior  longitudinal  bundle.  It  lies  behind 
the  pyramids  in  the  medulla. 

The  sensory  columns  of  the  cord  (Goll  and  Burdach)  are 
continued  into  the  medulla  oblongata  and  terminate  in  the 
funiculus  gracilis  and  euneatis.  They  increase  in  size  and  each 
develops  a  nucleus:  the  clava  and  cuneate  nucleus,  respectively. 
These  fibers  partly  form  the  restiform  bodies. 

The  decussation  of  the  sensory  fibers  takes  place  at  a  higher 
plane  than  that  of  the  motor  fibers.  It  is  also  called  the  decus- 
sation of  the  fillet  and  it  consists  of  the  decussating  fibers  de- 
rived from  the  clava  and  the  cuneate  nucleus.  These  fibers  are 
called  deep  arcuate  fibers.  After  decussating  the  fibers  are  con- 
tinued upward  behind  the  pyramids,  displacing  backward  the 
posterior  longitudinal  bundle  {fasciculus  longitudinalis  me- 
dialis). 

In  the  medulla  on  cross-section  are  seen  the  olivary  bodies 
(nucleus  olivaris  inferior),  which  contain  the  dentate   nuclei. 

The  restiform  bodies  (corpus  restiforme),  ot  inferior  cere- 
bellar peduncles,  are  formed  by  the  direct  cerebellar  tract,  the 
superficial  or  externa]  arcuate  fibers  (.fibres  arcuatce  external),  the 


316  HUMAN   ANATOMY. 

internal  arcuate  fibers  (fibrce  arcuatw  internee),  and  the  cere- 
bello-olivary  fibers. 

The  formatio  reticularis  is  seen  behind  the  pyramids  and 
the  olivary  bodies  in  the  medulla  oblongata.  It  is  composed  of 
the  deep  arcuate  fibers,  fibers  of  Gowers's  tract  and  the  antero- 
lateral ground-bundle. 

The  gray  matter  of  the  cord  is  continued  into  the.  medulla. 
The  anterior  horns  are  cut  off  and  displaced  by  the  decussation 
of  the  lateral  pyramidal  tract  and  the  posterior  horns  are  dis- 
placed outward  by  the  increase  in  size  of  the  posterior  sensory 
tracts.  The  latter  are  known  as  the  nucleus  of  Rolando  and  are 
capped  by  the  substantia  gelatinosa  Rolandi. 

The  central  canal  is  expanded  into  the  fourth  ventricle. 
The  gray  matter  forms  nuclei  for  the  cranial  nerves  in  the  floor 
of  the  fourth  ventricle. 

THE   INTERNAL   STRUCTURE   OF    THE   PONS  VAROLII. 

On  cross-section  the  pons  is  seen  to  consist  of  a  dorsal 
tegmental  part,  and  a  ventral  part,  or  crusta  (pars  basilaris 
pontis). 

The  crusta  is  composed  of  transverse  fibers  (fibers  from 
the  cerebellum  to  the  pons  and  from  the  nucleus  pontis  to  the 
cerebellum),  superficial  (fibrce  pontis  superficiales)  and  middle, 
which  go  to  form  the  middle  cerebellar  peduncles;  longitudinal 
fibers,  which  belong  to  the  pyramidal  tracts,  much  scattered; 
and  gray  matter,  which  here  forms  a  nucleus  called  the  nucleus 
pontis. 

The  tegmentum  of  the  pons  contains  a  thick  layer  of  gray 
matter,  which  forms  the  floor  of  the  fourth  ventricle,  and  from 
which  cranial  nerves  take  their  origin;  formatio  reticularis, 
which  is  the  continuation  upward  of  the  same  from'  the  medulla ; 
the  superior  olivary  nucleus  (nucleus  olivaris  superior)  ;  the 
posterior  longitudinal  bundle  (fasciculus  longitudinalis  medi- 
alis)  ;  the  fillet  (lemniscus)  ;  the  superior  cerebellar  peduncle 
(brachium  conjunctivum)  ;  and  the  corpus  trapezoides. 

The  fillet  occupies  a  position  between  the  crusta  and  teg- 
mentum, and  to  differentiate  it  from  a  tract  that  makes  its 
appearance  above  the  nucleus  of  the  third  nerve  is  called  the 
mesial  fillet  (lemniscus  medialis). 

The  other  tract  is  named  the  lateral  fillet. 

The  lateral  fillet  (lemniscus  lateralis)  is  composed  of 
longitudinal  fibers  which  take  origin  from  the-  nucleus  of  the 
eighth  cranial  nerve  (cochlearis)   of  the  same  side,  from  that 


THE    NERVOUS    SYSTEM. 


;;i; 


of  the  opposite  side,  and  from  the  superior  olive.  They  end 
in  the  inferior  quadrigeminal  body,  the  internal  geniculate  body 
and  a  few  in  the  superior  quadrigeminal  body. 


Mtitcoti 


nuclcaurf. 

J.lint.cap. 

Ext.  cap. 
■Is/. 

■MicL  lent. 
'■■Claus. 
■—Pl.intcap. 

.'Thai. 
...  C.j.m. 
..T.nud.caud. 

■Fimb 
■-M pp. 

..Post,  con 


ule;  Ext.  cap.,  external  capsule;   Tat,   Island  of  Retl;    Vucl    Umt 
Ducleus  lentiformis;  Clou.,  elaustrum;   P.  /.   int.  cap.,   posterior  Hrnii 
o*  internal  capsule;  Hipp    hippocampus;  Post,  cor.,    „  st  ,•],,•',  -,  . 
lateral   ventricle-.     (Whitehead,   after  Landois.)  'UOL,-"UI  Lor,ul  01 

The  mesial  fillet  has  been  described.     II  lakes  its  origiu  in 
the  medulla  i'mm  the  euneate  and  gracile  nuclei  of  the  opposite 


318  HUMAN    ANATOMY. 

side.  Some  of  its  fibers  end  in  the  superior  quadrigeminal  body, 
but  the  remainder  pass  through  the  subthalamic  tegmental, 
region  into  the  posterior  part  of  the  lateral  nucleus  of  the  optic 
thalamus.  Some  end  here,  while  some  are  continued  through 
the  thalamus,  enter  the  corona  radiata,  and  pass  to  the  posterior 
central  gyrus  of  the  Eolandic  region. 

THE  STRUCTURE  OF  THE  CEREBELLUM. 

On  section  the  gray  matter  of  the  cerebellum  is  found  to 
occupy  the  cortex  (substantia  corticalis)  ;  to  its  arborescent 
appearance  the  term  arbor  vitce  has  been  applied. 

The  white  matter,  medullary  body,  of  each  hemisphere  con- 
tains a  nucleus  of  gray  matter:  the  corpus  dentatum  (nucleus 
dentatus). 

The  middle  peduncles  connect  the  cerebellum  with  the  pons. 

The  inferior  peduncles,  or  restiform  bodies,  or  crura  ad 
medullam  (corpora  restiformia) ,  connect  the  medulla  and  cord 
with  the  cerebellum. 

The  superior  peduncles  (brachia  conjunctiva  cerebelli)  con- 
nect the  cerebellum  with  the  cerebral  cortex.  After  decussating 
below  the  corpora  quadrigemina  some  of  the  fibers  pass  to  the 
opposite  red  nucleus  (nucleus  tegmenti)  in  the  tegmentum  of 
the  crura  cerebri  passing  through  the  optic  thalamus  to  end  in 
the  Eolandic  region,  and  others  end  in  the  optic  thalamus. 
Each  superior  peduncle  contains  both  afferent  and  efferent 
fibers. 

The  cerebellar  cortex  consists  of  two  layers:  an  outer, 
molecular  layer,  and  an  inner,  granular  layer.  Between  these 
two  layers  is  a  single  layer  of  large  cells,  the  corpuscles  of 
Purkinje. 

THE  STRUCTURE  OF  THE  MID-BRAIN. 

The  mid-brain  consists  of  a  dorsal  part,  the  corpora  quad- 
rigemina, and  a  ventral  part,  the  crura  cerebri. 

It  is  tunneled  by  the  aqueduct  of  Sylvius,  which  connects 
the  fourth  ventricle  with  the  third  ventricle. 

The  upper  end  of  the  crura  cerebri  is  encircled  by  the  optic 
tract. 

On  section  the  crura  cerebri  show  a  ventral  and  lateral 
portion, — the  tegmentum, — and  a  dorsal  portion,  the  lamina 
quadrigemina.  The  ventral  portion  contains  the  substantia 
nigra.  The  fissure  of  Sylvius  is  surrounded  by  gray  matter, 
from  which  the  third  and  fourth  cranial  nerves  take  origin. 


THE    NERVOUS    SYSTEM. 


319 


SENSORY  MOTOR  AREA 


INTERNAL  CAPSULE 


FIRST  TEMPORAL 


CYBU8 

QUADR10BM1NATB 
BODIES^- ' 


INFERIOR  PEDUNCLE- 
OF  CEREBELLUM, 


SENSORY  DECUSSATION 
(DECUSSATION  OF  FILLET 


JWJCLEUS  CUNEATIS 


OOWERSB  TRACT 


EIGHTH  NERVE 
NINTH  NERVE 
TENTH  NERVE 


NUCLEUS  GRACILIS 


POSTEROMEDIAN  COLUMN, 
POSTEROLATERAL  COLUMN 


■DIRECT  CEREBEL1.AR  TRACT 


POSTERIOR  NERVE  ROOT 

Wia.  112. 
Diagram  of  sensory  tracts  from  spinal  cord  to  brain  (original). 


320  HUMAN    ANATOMY. 

The  inferior  or  posterior  quaclrigeminal  bodies  contain  the 
fibers  of  the  lateral  fillet  posteriorly  and  the  brachium  laterally. 

The  superior  or  anterior  quadrigeminal  bodies  consist  of 
four  strata:  stratum  zonale,  stratum  cinereum,  stratum  opti- 
cum  and  stratum  lemnisci.  The  mesial  and  upper  fillet  in  part 
end  in  the  latter,  which  also  contains  large  nerve  cells. 

Some  fibers  from  the  occipital  lobe  and  fibers  from  the 
retina,  conveyed  by  the  superior  brachium,  end  in  the  superior 
quadrigeminal  bodies. 

The  superior  cerebellar  peduncles  have  been  described ;  they 
connect  the  cerebellum  with  the  cerebral  cortex. 

The  red  nucleus  (nucleus  tegmenti)  is  found  in  the  teg- 
mentum. Some  of  the  fibers  of  the  superior  cerebellar  peduncles 
end  there. 

The  posterior  longitudinal  bundle  lies  in  the  tegmentum 
and  is  the  continuation  upward  of  the  tract  of  the  same  name 
in  the  medulla  and  pons.  It  is  connected  with  the  nuclei  of  the 
motor  nerves  of  the  muscles  of  the  eyeball. 

The  lateral  fillet  is  continued  upward  from  the  pons  in  the 
tegmentum.  Its  connections  with  the  superior  olivary  nuclei 
and  the  nuclei  of  the  eighth  nerve  have  been  described. 

The  mesial  fillet  likewise  is  continued  upward  from  the 
pons  in  the  tegmentum  of  the  crura.  The  course  of  the  fibers 
has  been  described. 

The  crusta  of  the  crura  contains  the  pyramidal  fibers  and 
the  corticopontine  fibers. 

THE    STRUCTURE    OF    THE     CEREBRUM. 

On  cross-section  the  cut  brain  surface  shows  an  outer  gray 
cortex  and  the  inner  white  matter  and  cavities  (centrum  ovale) , 
one  to  each  hemisphere :  the  lateral  ventricles.  The  white  mat- 
ter contains  certain  masses  of  gray  matter :  the  optic  thalami 
and  the  corpora  striata,  which  latter  are  on  each  side  of  the 
brain  divided  into  the  caudate  and  lenticular  nuclei  by  the 
internal  capsule.  Between  the  optic  thalamus  and  caudate 
nucleus  on  the  inside  and  the  lenticular  nucleus  on  the  outside 
passes  the  broad  band  of  white  fibers  known  as  the  internal  cap- 
sule (capsula  interna).  As  it  nears  the  cortex  the  fibers  spread 
out.  To  this  is  given  the  name  corona  radiata.  Between  the 
external  capsule  (capsula  externa)  and  the  cortex  of  the  island 
of  Eeil  is  seen  a  thin  sheet  of  gray  matter :  the  claustrum. 

The  white  matter  between  the  claustrum  and  the  lenticular 
nucleus  is  known  as  the  external  capsule.    On  horizontal  section 


THE  NERVOUS  SYSTEM. 


321 


CORTEX  OF  THE. 
«8NS0RY  MOTOR  AREA 


CORONA  RADIATA 


INTERNAL  CAPSULE  -V j 


fOURTH  NERVE 


P0N8 


•PINAL  CORD 


DECUSSATION  OF  PYRAMIDS 


ANTERIOR  PYRAMIDAL  TRACT 


ANTERIOR  COMMISSURE 


CAUDATE  NUCLEUS 
OPTIC  THALAMUS 


LENTICULAR  NUCLEUS 


THIRD  NERVR 


FIFTH  NERVE 


—  SIXTH  NERVH 
SEVENTH  NERVE 

NINTH  NERVB 

TENTH  NERVB 

ELEVENTH  NERVB 

TWELFTH  NERVB 


LATERAL  PYRAMIDAL  TRACT 


ANTERIOR  NKRVK  ROOT 


Fig.  113. 

Diagram  of  motor  tracts  from  brain  to  spinal  cord  (original). 

21 


322  HUMAN    ANATOMY. 

of  the  brain  the  internal  capsule  is  seen  to  be  bent  upon  itself, 
the  interval  between  the  optic  thalamus  and  the  caudate  nucleus. 
This  bend  is  called  the  genu  (genu  capsulce  internee).  One- 
third  of  the  capsule  lies  in  front  of  this  bend,  and  is  called  the 
anterior  limb  (pars  frontalis  capsulce  internee)  ;  the  portion 
behind  the  genu  is  called  the  posterior  limb  (pars  occipitalis 
capsular  internee). 

The  anterior  limb  contains  (1)  fibers  that  pass  from  the 
optic  thalamus  to  the  lenticular  and  caudate  nucleus,  (2)  fibers 
that  pass  from  the  optic  thalamus  to  the  cortex  of  the  frontal 
lobe,  and  (3)  fibers  that  pass  from  the  cortex  of  the  frontal 
lobe  to  the  nucleus  pontis. 

The  posterior  limb  contains  (1)  a  continuation  upward  of 
a  portion  of  the  mesial  fillet  and  the  superior  cerebellar  pedun- 
cles, (2)  the  pyramidal  tracts  or  motor  fibers  from  the  Eolandic 
area,  (3)  the  fibers  of  the  optic  radiation  (radiatio  occipito- 
thalamica),  (4)  the  fibers  of  the  auditory  radiation  (radiatio 
temporothalamica) ,  and  (5)  the  temporopontine  tract. 

The  opposite  sides  of  the  brain  are  connected  by  the  com- 
missural fibers.  Convolutions  on  the  same  side  are  connected 
by  association  fibers.  Projection  fibers  are  those  which  unite 
the  cerebral  cortex  with  nuclei  in  lower  levels.  They  pass  prin- 
cipally through  the  corona  radiata. 

The  cerebral  cortex  consists  of  five  layers :  the  stratum 
zonale,  the  layer  of  small  pyramidal  cells,  the  layer  of  large 
pyramidal  cells,  the  layer  of  polymorphous  cells  and  a  layer  of 
fusiform  cell-bodies. 

CRANIAL    NERVES. 

The  cranial  nerves  (nervi  cerebral  es)  consist  of  twelve 
pairs,  as  follows : — 

1.  Olfactory,  8.  Auditory    (portio  mollis), 

2.  Optic,  9.  Glossopharyngeal, 

3.  Motores  oculorum,  10.  Pneumogastric    (vagus,  or  par 

4.  Pathetici,  vagum ) , 

5.  Trifacial,  11.  Spinal   accessory, 

6.  Abducentes,  12.  Hypoglossal. 

7.  Facial    (portio  dura), 

1.  Olfactory  nerve  (n.  olfactorius) ,  special  nerve  of 
smell.  A  number  of  nerves  (20)  arise  from  the  olfactory  bulb 
or  lobe  of  the  brain.  Superficial  origin  of  the  tract  by  roots : 
internal  from  frontal  lobe,  middle  or  gray  root  from  the  olfac- 
tory tubercle   (trigonum  olfactorium)   between  the  other  roots 


THE    NERVOUS    SYSTEM. 


323 


of  the  tract,  and  external  from  the  middle  lobe;  deep  origin, 
from  gyrus  fornicatus,  uncinate  gyrus  of  limbic  lobe;  course, 
roots  unite,  pass  forward,  and  form  bulbus  olfactorius  (from 
this  the  olfactory  nerves  are  given  off)  ;  exit,  foramina  of  crib- 
riform plate  of  ethmoid;  distribution,  by  three  groups  to  mu- 


FiG.  114. 

Scheme  of  the  nuclei   and   root-fibers  of  the  cranial   nerves. 
(Whitehead,  after  Edinger.) 

( Schneider ian)  membrane  of  nares,  inner  to  septum  nasi, 
middle  to  roof  of  nasal  fossa,  outer  to  superior  turbinated  bone. 
2.  Optic  nerve  (n.  opticus),  special  nerve  of  sight;  super- 
ficial origin,  optic  chiasms  or  commissure  formed  by  union  of 
the  optic  tracts.    The  commissure  and  tracts  contain  intercere- 


324 


HUMAN   ANATOMY. 


bral  fibers,  the  cerebroretinal  fibers  of  the  same  side,  and  the 
cerebroretinal  fibers  of  opposite  sides.  Deep  origin,  the  optic 
tracts  arise  from  optic  thalamus,  the  upper  corpora  quadri- 
gemina  and  corpora  geniculati;  course,  diverge  and  pass  for- 


FiG.  115. 

Base  of  brain  and  cranial  nerves;  1,  olfactory  bulb;  2,  optic 
nerves;  4,  tractusi  opticus;  5,  crus  cerebri;  6,  third  pair  of  nerves; 
7,  fourth  pair  of  nerves;  8,  fifth  pair  of  nerves;  9,  sixth  pair  of  nerves; 
10,  pyramid;  11,  olivary  body;  22,  pons  Varolii;  24,  seventh  and  eighth 
pairs  of  nerves;  25,  ninth,  tenth  and  eleventh  pairs  of  nerves;  26, 
twelfth  pair  of  nerves;  27,  cerebellum. 

ward;  exit,  optic  foramen;  distribution,  to  ganglion  cells  in  the 
retina. 

3.  Motor  oculi   (n.  oculomotorius) ,  motor  nerve;  super- 
ficial origin,  inner  surface  of  crus  cerebri ;  deep  origin,  from  the 


Forehtad  ttud  Stalp 


'ouppa-Mytlidaad^arrh^ad 


la  anJ  Itn-krymiil  >w 


[/al'tr'ilil 


PIG.    116. 

Optic,  oculomotor,  trochlear,  and  trifacial  nerves, 


THE  NERVOUS  SYSTEM.  325 

oculomotor  nucleus  in  floor  of  aqueduct  of  Sylvius;  course,  from 
inner  side  of  eras  cerebri  passes  forward,  descends  along  exter- 
nal wall  of  cavernous  sinus;  exit,  sphenoidal  fissure  between 
two  heads  of  external  rectus  muscle;  distribution,  by  superior 
and  inferior  divisions,  to  all  the  ocular  muscles  (including  the 
iris)   except  the  external  rectus  and  superior  oblique. 

4.  Trochlear  (to,  trochlearis — pathetic),  motor  nerve; 
superficial  origin,  from  valve  of  Yieussens,  on  outer  side  of  crus 
cerebri;  deep  origin,  from  floor  of  aqueduct  of  Sylvius;  course, 
outer  side  of  crus  cerebri,  through  outer  wall  of  cavernous  sinus ; 
exit,  sphenoidal  fissure;  distribution,  to  superior  oblique  muscle. 

5.  Trifacial,  or  Trigeminus  (to.  trigeminus),  common 
sensation,  taste  and  motion  ;  superficial  origin,  by  two  roots, 
like  a  spinal  nerve,  from  the  side  of  the  pons  Varolii;  deep 
origin,  the  motor  root,  from  (1)  a  nucleus  in  the  floor  of  the 
aqueduct  of  Sylvius  (descending  motor  root),  and  (2)  from  a 
nucleus  in  the  pons  (these  join  to  form  the  motor  root)  ;  the 
sensory  root  ends  in  two  terminal  nuclei — (1)  the  sensory 
nucleus  of  the  fifth  nerve  in  the  pons,  and  (2)  the  substantia 
gelatinosa  Rolandi  in  the  pons,  medulla  and  the  spinal  cord  as 
far  down  as  the  second  cervical  nerve;  course,  passes  forward 
to  apex  of  petrous  portion  of  temporal  bone,  where  the  sensory 
root  enters  Gasserian  ganglion,  the  motor  passing  beneath,  and 
later  joins  a  branch  of  the  ganglion.  It  divides  into  three 
branches — ophthalmic,  superior  maxillary  and  inferior  maxil- 
lary; exit,  ophthalmic  by  sphenoidal  fissure,  superior  maxillary 
by  foramen  rotundum,  inferior  maxillary  by  foramen  ovale. 

Ophthalmic  nerve  (n.  ophthalmicus),  entirely  sensory,  sup- 
plies lachrymal  gland,  upper  eyelid,  skin  and  muscles  of  fore- 
head, eyebrow,  aose,  eyeball  (ciliary  muscle,  iris,  etc.),  mucous 
membrane  of  eyelids  and  nose  and  the  ciliary  ganglion. 

Its  branches  are: — 

Lachrymal    (n.  lacrimalis) ; 
Frontal  ( n.  frontalis) ; 
Naaal   (n.  nasociliaris) . 

Superior  maxillary  nerve  (to.  maxillaris),  entirely  sensory 
also;  supplies  sensation  to  upper  jaw,  teeth,  hard  and  soft 
palates,  tonsils,  gums,  antrum  of  Eighmore,  muscles,  skin  and 
mucous  membrane  of  lower  eyelid,  muscles  and  skin  of  cheeks 
and  upper  lip,  and  mucous  membrane  of  floor  of  nares. 


326 


HUMAN    ANATOMY. 


Middle  superior  den- 
tal ( ramus  alveo- 
la/ris  superior  me- 
dius ) , 

Anterior  superior  den- 
tal (ramus  alveo- 
laris  superior  ante- 
riores ) , 


Palpebral  ( rami  pal- 
pebrales  inferiores) , 

Nasal  ( rami  nasales 
interni) , 

Labial  (rami  labiates 
superiores ) . 


Its  branches  are  :- 

Meningeal  ( n.  menin- 
geus  medius) , 

Orbital  ( n.  zygoma- 
ticus ) , 

Spheno-palatine  ( n. 
sphenopalatine ) , 

Posterior  superior  den- 
tal (rami  alveolcures 
superiores  posteri- 
or es  ) , 

Inferior  maxillary  nerve  (n.  mandibularis)  consists  of  two 
portions:  anterior  or  motor,  and  posterior  or  sensory,  having 
a  threefold  function,  because  one  of  its  branches,  the  lingual,  is 
joined  by  the  chorda  tympani  nerve  (given  off  from  the  facial 
nerve),  which  conveys  gustatory  fibers  to  the  anterior  two-thirds 
of  the  tongue.  It  supplies  motion  to  all  the  muscles  of  masti- 
cation (except  to  buccinator),  anterior  belly  of  digastric  and 
mylohyoideus ;  sensation  to  skin  of  ear,  lower  part  of  face,  lower 
lip  and  tongue/  Previous  to  its  division,  the  primary  trunk 
gives  off  the  recurrent  (n.  spinosus)  and  the  internal  pterygoid 
(n.  pterygoideus  internus).  Immediately  below  the  base  of  the 
skull  it  divides  into  an  anterior  and  a  posterior  portion.  Its 
branches-  are : — 


Posterior  Portion. 

Auriculotemporal  (n.  auriculotem- 
poral ) , 

Inferior  dental  (n.  alveolaris  in- 
ferior ) , 

Lingual   ( n.  lingualis ) . 


Anterior  Portion. 
Masseteric  (n.  mussetericus) , 
Deep     temporal      (nn.     temporales 

profundi )     ( 2 ) , 
Buccal    (n.  buccinatorius) , 
Pterygoid    (n.   pterygoideus   exter- 

nus ) , 

The  fifth  nerve  has  four  ganglia  connected  with  it: — 

(a)  Ophthalmic,   or   lenticular    (ganglion  ciliare)  ■ 

(b)  Sphenopalatine,  or  Meckel's    (ganglion  sphenopalatinum)  ; 

(c)  Otic,  or  Arnold's    (ganglion  oticum)  ; 

(d)  Submaxillary     (vide    Sympathetic    System)      (ganglion    sub- 
maxillar e)  . 

6.  Abducens  (n.  abducens),  motor;  superficial  origin, 
pyramidal  body  and  pons  Varolii;  deep  origin,  floor  of  fourth 
ventricle;  course,  passes  forward  in  cavernous  sinus;  exit,  sphe- 
noidal fissure;  distribution,  to  external  rectus  muscle. 

7.  Facial  (n.  facialis),  motor  nerve;  superficial  origin, 
lateral  tract  of  medulla  and  pons  Varolii;  deep  origin,  from  a 
nucleus  in  the  pons,  deeply  placed,  from  which  the  fibers  ascend 


THE    NERVOUS    SYSTEM. 


337 


k  §.■§  &?  ?s 


ill 


Fig.  117. 


328 


HUMAN    ANATOMY. 


close  to  the  floor  of  the  fourth  ventricle,  where  they  form  the 
eminentia  teres,  arch  over  the  nucleus  of  the  sixth  nerve,  and 
then  emerge  (this  nerve  carries  some  sensory  fibers,  probably 
gustatory  fibers  from  the  tongue,  through  the  chorda  tympani 
nerve  to  the  pars  intermedia  [n.  intermedins],  near  the  nucleus 
of  the  ninth  nerve)  ;  course,  forward  and  outward,  through  in- 
ternal auditory  meatus,  aqueductus  Fallopii  and  inner  wall  of 
tympanum;  exit,  stylomastoid  foramen;  distribution,  to  muscles 
of  expression,  buccinator,  and  platysma,  posterior  belly  of  digas- 
tric, stylohyoid  attrahens  and  retrahens  aurem  muscles,  to 
laxator  tympani  and  stapedius  through  tympanic  branch,  dorsal 
surface  of  tongue  through  chorda  tympani,  and  levator  palati, 
and  azygos  uvulae  muscles  through  Vidian.  In  its  course 
through  the  temporal  bone  it  communicates  with  many  impor- 
tant nerves;  in  the  internal  auditory  meatus,  with  auditory 
(portio  mollis)  ;  in  aqueductus  Fallopii,  with  otic  ganglion,  by 
the  small  petrosal;  Meckel's  ganglion,  by  the  large  petrosal 
nerve ;  the  sympathetic  of  the  great  meningeal,  by  the  external 
petrosal  nerve;  and  at  its  exit  from  the  stylomastoid  foramen, 
with  the  glossopharyngeal,  pneumogastric,  auriculotemporal, 
auricularis  magnus  and  the  carotid  plexus.     Its  branches  are : — 

On  the  Face. 

{Temporal    (rami  temporales) . 
Malar    (rami  zygomatics). 
Infraorbital    (rami   buccales). 


In  Aqueductus 
Fallopii. 

Tympanic 
( n.  stapedius ) . 
Chorda  tympani. 


^ 


r Buccal    (rami  buccales). 

r,       .     .     .  ,         j  Supramaxillary    (ramus   mar- 
Cervicoiacial,      <       £•     7-  •'-,-, v  7    > 

'        ',       gnnahs  mandioukc) . 

I  Inframaxillary   (ramus  colli). 

Posterior  auricular, 

Stylohyoid    (ramus  stylohyoideus) , 
Digastric    (ramus  digastricus) . 


8.  Auditory  (n.  acusticus),  special  nerve  of  hearing,  con- 
sists of  two  portions — (1)  cochlear,  or  auditory  portion,  and 
(2)  vestibular,  or  fibers  whose  function  is  to  localize  position. 

The  former  pass  from  the  cochlea  to  the  (1)  accessory 
auditory  nucleus  in  the  medulla,  and  (2)  to  the  lateral  acoustic 
tubercle  in  the  medulla.  These  fibers,  by  means  of  the  lateral 
fillet,  communicate  with  the  inferior  corpora  quadrigemina. 

The  vestibular  fibers  (fibrce  vestibularis)  pass  from  the 
vestibule  to  the  external  and  internal  dorsal  nuclei  in  the  floor 
of  the  fourth  ventricle,  and  by  the  sensory  decussation  to  the 
nucleus  cuneatus. 


THE    NERVOUS    SYSTEM. 


329 


Fiu.  US. 


330  HUMAN   ANATOMY. 

Superficial  origin,  from  groove  between  olivary  and  resti- 
form  bodies;  course,  winds  around  restiform  body,  and  passes 
forward  to  internal  auditory  meatus,  with  the  facial;  distribu- 
tion, to  internal  ear  by  two  branches : — 

Vestibular,  and  Cochlear    {vide  Ear,  p.  370). 

9.  Glossopharyngeal  (n.  glossopharyngeus) ,  or  ninth, 
nerve  of  motion,  common  sensation,  and  taste ;  superficial  origin, 
from  medulla  oblongata,  between  olivary  and  restiform  bodies ; 
deep  origin^,  from  motor  and  sensory  gray  nuclei  in  floor  of 
fourth  ventricle;  course,  passes  outward  across  flocculus;  exit, 
jugular  foramen,  in  separate  sheath,  in  front  of  pneumogastric 
and  spinal  accessory,  having  two  gangliform  enlargements  upon 
it — jugular,  and  the  petrous  or  ganglion  of  Andersch;  dis- 
tribution, to  mucous  membrane  of  fauces,  tonsil,  pharynx  and 
middle  ear,  muscles  of  the  pharynx,  and  special  sense  of  taste 
to  the  base  and  sides  of  the  tongue.     Its  branches  are: — 

Tympanic    ( Jacobson's ) ,     (n.    tym-  Pharyngeal   branches    (rami   phar- 

pamcus ) ,  yngei ) , 

Carotid  branches    (n.   caroticotym-  Tonsillar    branches     (rami    tonsil- 

panicus  superior  et  n.  carotico-  lares), 

tympanicus  inferior ) ,  Lingual  branches  ( rami  linguales ) . 
Muscular   branches    (ramus    stylo- 

pharyngeus ) , 

10.  Pneumogastric,  vagus,  or  par  vagum  (n.  vagus), 
tenth  nerve,  motor  and  sensory;  superficial  origin,  from  groove 
between  olivary  and  restiform  bodies  by  a  dozen  filaments ;  deep 
origin,  from  nuclei  in  floor  of  fourth  ventricle;  course,  passes 
outward  across  the  flocculus;  exit,  jugular  foramen  in  a  com- 
mon sheath  with  the  spinal  accessory  nerve;  distribution  (not 
definitely  known),  motor  nerve  to  the  organs  of  respiration  and 
voice,  and  a  motor  and  sensory  nerve  to  heart,  esophagus, 
pharynx  and  stomach.    It  branches  are  : — 

Meningeal    (ramus   meningeus) ,  Cervical     cardiac     (rami    carcliaci 

Auricular      (Arnold's)      (ramus  superior  es) , 

auricularis),  Thoracic    cardiac     (rami    cardiaci 

Pharyngeal    (ramus  pharyngcus) ,  inferior -es) , 

Superior  laryngeal,  Anterior  pulmonary, 

Recurrent  laryngeal    (n.  laryngeus  Posterior  pulmonary, 

inferior),  Esophageal   (rami  esophagei) , 

Gastric    (rami  gastrici) . 

It  also  communicates  with  the  left  hepatic  sympathetic 
plexus. 


THE    NERVOUS    SYSTEM.  331 

11.  Spiral  accessory  (n.  accessorvus) ,  eleventh,  motor 
nerve;  superficial  origin,  from  lateral  tract  of  medulla  and 
spinal  cord  as  low  as  sixth  cervical  nerve;  deep  origin,  spinal 
portion  from  anterior  horn  of  gray  matter;  accessory  portion 
from  gray  nucleus  in  floor  of  fourth  ventricle;  course,  the  spinal 
portion  enters  the  skull  through  the  foramen  magnum,  and  joins 
the  accessory  portion  in  the  jugular  foramen  ;  exit,  jugular  fora- 
men in  sheath  with  the  pneumogastric ;  distribution,  to  sterno- 
cleidomastoid and  trapezius  muscles,  communicating  with  the 
cervical  plexus  and  pharyngeal  and  laryngeal  branches  of  pneu- 
mogastric. 

12.  Hypoglossal  (n.  lnjpoglossus) ,  or  twelfth  nerve,  motor 
nerve  of  tongue;  superfii  ial  origin,  from  groove  between  olivary 
and  pyramidal  bodies  by  about  a  dozen  filaments;  deep  origin, 
from  gray  nucleus  at  lowest  part  of  floor  of  fourth  ventricle; 
exit,  anterior  condyloid  foramen;  distribution,  to  the  omohyoid 
(both  bellies),  sternohyoid,  sternothyroid,  thyrohyoid,  and  mus- 
cles of  the  tongue — styloglossus,  hyoglossus,  geniohyoid,  genio- 
hvoglossus,  communicating  with  the  pneumogastric,  sympa- 
thetic, first  and  second  cervical  and  gustatory  nerves.  Its 
branches  are: — 

Descendens  hypoglossi    (ramus  descendens) ,  Muscular, 

Thyrohyoid    '{ramus    thyreohyoid-eus) ,  Meningeal. 

Membranes  of  the  Cord.< — The  membranes  of  the  spinal 
cord  are  three — the  dura  mater,  arachnoid  and  pia  mater. 

Dura  mater  (dura  mater  spinalis)  is>  a  loose  fibrous  sheath, 
continuous  with  the  dura  of  the  brain,  and  from  which  it  differs 
in  not  inclosing  the  venous  sinuses,  not  dipping  into  the  fissures 
of  the  cord,  and  not  being  adherent  to  the  bony  canal.  From 
the  latter  it  is  separated  by  the  venous  plexuses  (plexus  venosi 
vertebrates  interni)  and  some  connective  tissue. 

It  extends  the  whole  length  of  the  canal,  from  the  foramen 
magnum  (to  which  it  is  attached)  to  the  top  of  the  sacrum. 

Arachnoid  (araclmoidea  spinalis)  is  a  delicate  serous  sac, 
continuous  above  with  the  cerebral  arachnoid,  inclosing  the  pia 
mater,  from  which  it  is  separated  by  an  interval — the  sub- 
arachnoidean  space  (cavum  subarachnoideale) .  It  is  filled  with 
the  cerebrospinal  fluid  (liquor  cerebrosjnnalis).  The  outer  sur- 
face of  the  arachnoid  is  in  contact  with  the  dura,  the  space 
between  them  being  called  the  subdural  space  (cavum  subdurale). 

Pia  mater  (pia  mater  sjnnalis)  is  a  fibrous  membrane, 
closely  adhering  to  the  cord  and  forming  its  neurilemma.  Over 
the  anterior  median  fissure,  if  is  strengthened  by  a  fibrous  hand 


332  HUMAN   ANATOMY. 

— the  linea  splendens — .and  laterally  has  the  lig amentum  den- 
ticulatum.  It  terminates  below  the  cord  as  the  plum  terminate 
— a  slender  filament. 

THE    SPINAL    CORD. 

The  spinal  cord  {medulla  spinalis)  is  the  elongated  portion 
of  the  cerebrospinal  axis  contained  in  the  spinal  canal.  Its 
length  is  about  sixteen  to  eighteen  inches,  extending  from  the 
medulla  above  to  the  lower  border  of  the  first  lumbar  vertebra 
below,  where  it  terminates  in  the  cauda  equina  by  a  slender  pro- 
longation of  gray  substance,  called  the  conus  medullaris. 

It  presents  two  enlargements,  the  upper  or  cervical  (intu- 
mescentia  cervicalis),  extending  from  the  third  cervical  to  the 
second  dorsal  vertebra,  and  the  lower  or  lumbar  (intumescentia 
lumbalis),  about  the  position  of  the  second  or  third  dorsal 
vertebra.  It  is  divided  into  two  lateral  halves  by  the  anterior 
(fissura  mediana  anterior)  and  posterior  median  fissures  (sulcus 
medianus  posterior),  united  in  center  by  the  commissure.  The 
lateral  portions  are  subdivided  by  anterolateral  (sulcus  lateralis 
anterior)  and  posterolateral  fissures  (sulcus  lateralis  posterior) 
into  anterior  lateral  and  posterior  lateral  columns,  and  poste- 
riorly a  narrow  fissure  separates  the  posterior  median  column 
from  the  posterior  median  fissure.  The  gray  substance  occupies 
the  center  of  the  cord,  and  is  arranged  into  two  crescentic 
masses  connected  together  by  the  gray  commissure  (commissura 
grisea).  The  posterior  horn  (columna  grisea  posterior)  forms 
the  apex  cornu  (apex  columna  grisea  posterior),  from  which 
arises  the  posterior  root  of  the  spinal  nerves.  The  anterior  horn 
(columna  grisea  anterior)  is  thick  and  short,  and  affords  origin 
to  the  anterior  root  of  the  nerve.  The  gray  commissure  contains 
throughout  its  whole  length  a  minute  canal — the  central  canal, 
or  ventricle  of  the  cord  (canalis  centralis),  continuous  above 
with  the  fourth  ventricle. 

SPINAL    NER.VES. 

The  spinal  nerves  (nervi  spinales)  consist  of  thirty-one 
pairs,  arranged  in  the  following  order:  cervical,  eight  pairs; 
dorsal,  twelve  pairs;  lumbar,  five  pairs;  sacral,  five  pairs; 
coccygeal,  one  pair. 

Each  of  the  spinal  nerves  arises  by  two  roots,  an  anterior 
(radix  anterior)  or  motor  and  a  posterior  (radix  posterior)  or 
sensory.  The  fibers  of  the  anterior  root  arise  from  the  antero- 
lateral columns,  originating  deeply  in  the  gray  mattei   of  the 


THE    NERVOUS    SYSTEM. 


333 


Fig.  119. 


334  HUMAN    ANATOMY. 

cord.  The  posterior  roots  arise  at  the  posterolateral  fissure,  also 
originating  deeply  in  the  gray  matter  of  the  cord.  The  pos- 
terior roots  have  each  a  ganglion  (ganglia  spinales)  developed 
upon  it — except  sometimes  the  first  cervical.  These  roots  unite 
and  the  nerve  then  subdivides  into  two  branches,  both  having 
motor  and  sensory  fibers.  The  posterior  branches  are  small; 
they  supply  the  skin  and  muscles  of  the  back. 

The  anterior  branches  supply  the  neck,  front  and  sides  of 
the  trunk,  and  the  extremities. 

Cervical  Plexus  (plexus  cervicalis). — The  cervical  plexus 
is  formed  by  the  anterior  divisions  of  the  first  to  the  fourth 
cervical  nerves.    It  is  covered  by  the  sternomastoid  muscle,  and 


Fig.  120. 

Section  of  spinal  cord  and  membranes:  1,  dura  mater;  2,  arach- 
noid membrane;  3,  ganglion  on  posterior  root;  4,  anterior  root  of 
spinal  nerve;  5,  5,  subarachnoid  space;  6,  posterior  branch  of  spinal 
nerve;   7,   anterior  branch  of  spinal   nerve. 

rests  upon  the  scalenus  medius  and  levator  anguli  scapulae  mus- 
cle.   It  gives  off: — 

Superficial. 
Superficialis     colli      (n.     cutaneus      Occipitalis    minor     (n.    occipitalis 

colli),  minor), 

Auricularis     magnus      (n.     auricu-       Supraclavicular     (nn.    supi'aclavic- 

laris  magnus),  ulares) . 

Deep. 
Deep   (Internal  Series)  Deep    (External  Series) 

Communicating,  Communicating, 

Muscular,  Muscular. 

Phrenic   ( n.  phrenicus ) , 
Communicantes  hypoglossi, 

The  phrenic  nerve,,  or  internal  respiratory  of  Bell,  is  de- 
rived from  the  third  and  fourth  cervical  nerves,  with  a  branch 
from  the  fifth.  It  descends  into  the  chest  between  the  sub- 
clavian artery  and  vein,  between  the  pericardium  and  the 
pleura,    to    the    diaphragm,    to   Avhich   it   is   distributed    (rami 


THE    NERVOUS    SYSTEM. 


335 


Fig.  121. 


336  HUMAN    ANATOMY. 

phrenicoab  dominates) .  The  course  of  the  two  nerves  differs  in 
the  thorax  (vide  Mediastinum). 

The  beachial  plexus  (plexus  brachialis)  is  formed  by 
the  anterior  branches  of  the  four  lower  cervical  and  the  hrst 
upper  dorsal  nerves — the  fifth,  sixth  and  seventh  forming  one 
cord,  and  the  eighth  cervical  and  first  dorsal  another  cord. 
Below  the  line  of  the  clavicle  (pars  infracldvicularis)  both 
these  trunks  divide,  the  adjacent  cords  of  the  two  upper  uniting 
to  form  the  posterior  (fasciculus  posterior) ,  and  the  remaining 
cords  forming  the  outer  (fasciculus  lateralis)  and  inner  (fascic- 
ulus medius)  cords  respectively,  receiving  their  names  from 
their  relative  position  to  the  subclavian  artery.  Each  of  these 
cords  again  bifurcates,  the  adjacent  divisions  at  the  outer  end- 
ing of  the  cords,  uniting  over  the  artery  to  form  the  median 
nerve,  the  other  divisions  forming  the  musculocutaneous,  ulnar, 
circumflex  and  musculospiral,  the  two  latter  being  the  divisions 
of  the  posterior  cord.     Its  branches  are : — 

Above  the  clavicle  (pars  supraclavicularis)  : — 

Communicating,  arises  from  the  fifth  cervical,  and  passes 
to  the  phrenic; 

Muscular  (rami  muscular es),  supply  the  scaleni,  rhom- 
boidii,  longus  colli  and  subclavius; 

Posterior  thoracic  (n.  thoracalis  longus),  long  thoracic,  or 
external  respiratory  of  Bell,  arises  by  five  roots  from  the  fifth 
to  seventh  cervical  nerves,  which  unite  within  the  scalenus 
medius  muscle  and  descend  to  supply  the  serratus  magnus; 

Suprascapular  (n.  suprascapularis) ,  passes  beneath  the  tra- 
pezius, through  the  suprascapular  notch,  to  supply  the  shoulder- 
joint  and  supraspinatus  muscle. 

Below  the  clavicle  (pars  subclavicularis)  : — 

The  anterior  thoracic  nerves  (nn.  thoracales  anteriores)  are 
two  in  number :  an  external  branch  from  the  outer  cord  and  an 
internal  from  the  inner  cord.  The  former  supplies  the  pec- 
toralis  major  and  the  latter  the  pectoralis  minor,  and  sending 
branches  to  the  pectoralis  major. 

The  subscapular  nerves  (nn.  subscapulares)  are  three  in 
number.  The  upper  subscapular  supplies  the  subscapular  mus- 
cle, the  lower  subscapular  nerve  supplies  the  teres  major  and 
subscapularis,  the  middle  or  long  subscapular  supplies  the  latis- 
simus  clorsi. 

The  circumflex  nerve  (n.  axillaris)  accompanies  the  pos- 
terior circumflex  artery,  passing  through  the  space  formed  be- 
tween the  teres  major,  teres  minor  and  long  head  of  the  triceps 
to  supply  the  shoulder  joint  and  skin  over  the  shoulder  and  the 


THE    NERVOUS    SYSTEM.  337 

neighboring  muscles.  It  gives  off  two  branches,  an  upper  and 
a  lower  branch. 

The  musculocutaneous  nerve  (n.  musculocutaneus)  pierces 
the  coracobrachial  muscle  and  descends  the  arm  to  supply  the 
brachialis  anticus.  biceps,  coracobrachial  and  the  skin  of  the 
forearm.  At  the  outer  border  of  the  tendon  of  the  biceps,  above 
the  elbow,  it  becomes  superficial  and  divides  into  two  brandies 
— the  anterior  descending  the  radial  side  of  the  forearm  to  the 
wrist  and  supplying  the  skin  of  that  part,  the  posterior  branch 
descending  the  back  part  of  the  radial  side  of  the  forearm  to 
the  wrist.     It  supplies  skin  of  lower  third  of  forearm. 

The  internal  cutaneous  nerve  (n.  cvianeus  antibracliii  me- 
dialis)  descends  the  inner  side  of  the  arm  together  with  the 
basilic  vein  to  about  its  middle,  where  it  becomes  cutaneous, 
supplying  the  skin  of  this  region.  It  has  an  anterior  and  a 
posterior  branch. 

The  lesser  internal  cutaneous  nerve  of  Wrisberg  (n.  cuta- 
neus  brachii  medialis)  is  derived  from  the  inner  cord,  and 
receives  filaments  from  the  eighth  cervical,  first  dorsal  and  the 
intercostohumeral  nerve,  and  is  distributed  to  the  skin  on  the 
inner  side  of  the  arm. 

The  median  nerve  (n.  medianus),  formed  by  a  root  from 
the  outer  and  inner  cord  of  the  brachial  plexus,  descends  the 
arm,  crossing  the  brachial  artery  from  its  outer  to  its  inner  side 
at  the  bend  of  the  elbow.     Its  branches  are : — - 

Muscular  (rami  muscular es)  branches,  supply  all  the  superficial 
anterior   muscles  except  the  flexor  carpi   ulnaris; 

Anterior  interosseous  (n.  intcrosseus  antibracMi  volaris),  supplies 
all  the  3eep  anterior  muscles  except  the  inner  half  of  the  flexor  pro- 
fundus  digiforum; 

Palmar  cutaneous  (ramus  cutan&us  palmaris  n.  mediarri),  crosses 
above  the  annular  ligament,  divides  into  two  branches  to  supply  tha 
ball  <»f  the  thumb  and  the  palmar  surface  of  the  hand; 

Branches  10  the  muscles  of  the  thumb  (r<nni  musculares) ,  sup- 
ply the  opponens,  outer   head  of  the  small    flexor,   and  the  abductor; 

Digital  branches  (mi.  digitales  volares  proprii),  supply  both  sides 
of  the  thumb,  index  and  middle  and  the  radial  side  of  the  ring  finger. 

The  ulnar  nerve  (n.  ulnaris)  descends  the  inner  side  of  the 
axillary  artery  to  the  middle  of  the  arm,  where  it  crosses  the 
internal  head  of  the  triceps,  and  accompanies  the  inferior  pro- 
funda artery  to  the  elbow,  where  it  passes  between  the  heads  of 
the  flexor  carpi  ulnaris.     Its  branches  are,  in  the  forearm: — 

Irticular   (elbow),  supplies  tin1  elbow   joint; 

Muscular  [rami  musculares),  to  inner  half  of  the  deep  flexors  and 
flexor  carpi  ulnaris; 

22 


338  HUMAN    ANATOMY. 

Cutaneous  (ramus  cutaneus  palmaris),  supplies  the  skin  of  the 
palm; 

Dorsal  cutaneous  (ramus  dor  salts  manus) ,  supplies  both  sides  of 
the  little  finger  and  the  ulnar  side  of  the  ring  finger; 

Articular    (wrist),  supply  the  wrist  joint. 

In  the  hand : — 

Superficial  palmar  (ramus  superficialis  n.  ulnaris) ,  supplies  the 
skin  of  both  sides  of  the  little  and  the  ulnar  side  of  the  ring  finger  and 
palmaris  brevis  muscle; 

Deep  palmar  (ramus  profundus  n.  uhvaris) ,  supplies  the  inter- 
ossei,  lumbricales,  adductor  pollici,  and  inner  head  of  flexor  brevis 
pollicis. 

The  musculospiral  nerve  (n.  radial  is) ,  derived  from  the 
posterior  cord  of  the  brachial  plexus,  descends  the  arm  in  front 
of  the  teres  major  and  latissimus  dorsi  muscle,  accompanies  the 
superior  profunda  artery  through  the  musculospiral  groove  to 
the  outer  side  of  the  elbow,  between  the  supinator  longus  and 
the  brachialis  anticus,  where  it  divides  into  the  radial  and  pos- 
terior interosseous  nerves.     Its  branches  are : — 

Muscular  (rami  musculmes  n.  radialis),  supply  the  supinator  lon- 
gus, external  carpi  radialis  longior,  triceps,  anconeus  and  brachialis 
anticus ; 

Radial  (ramus  superficialis  n.  radialis),  descends  in  the  course  of 
the  radial  artery  to  three  inches  above  the  -wrist,  where  it  becomes  super- 
ficial, and  supplies  the  adjoining  sides  of  the  thumb  and  index,  index 
and  middle,  middle  and  ring  fingers. 

Cutaneous,  supply  the  outer  side  of  the  arm,  elbow,  and  radial  side 
of  forearm  and  wrist; 

Posterior  interosseous  (ramus  profundus  n.  radialis),  passes 
through  the  supinator  brevis  muscle,  and  supplies,  as  it  descends,  all 
the  posterior  brachial  and  radial  muscles,  except  those  supplied  by  the 
muscular  branches  of  the  ulnar.     It  has  a  ganglion  upon  it. 

Dorsal  Nerves. — The  posterior  divisions  of  the  dorsal 
nerves  (nn.  thoracales)  subdivide  into  the  external  and  internal 
branches  to  supply  the  muscles  of  the  skin  of  the  back.  The 
anterior  [rami  anterior es)  divisions  of  the  dorsal  nerves,  inter- 
costal nerves  (nn.  intercostales) ,  twelve  in  number,  supply  the 
walls  of  the  abdomen  and  thorax.  They  are  divided  into  two 
sets — the  upper  six,  distributed  for  the  most  part  to  the  walls 
of  the  chest,  and  the  lower  six,  to  the  walls  of  the  chest  and 
abdomen.  The  upper  six  dorsal  nerves  run  between'  the  two 
sets  of  the  intercostal  muscles,  accompanied  by  the  intercostal 
vessels,  to  supply  the  skin  over  the  front  of  the  chest  and  the 
mammas.    Their  branches  are : — 

Lateral  cutaneous  (rami  cutanei  laterales  pectorales) ,  divide  into 
two  branches,  anterior  and  posterior; 


Toouta-partoffivutofl'htgli 
Tofroat  ol~Th,.yIi.\ 


To'skinoreruuurMklf. 


Pig.  1X2. 
Lumbar  plexus  aud  brancbe 


THE    NERVOUS    SYSTEM.  339 

Anterior  branches  (rami  unto  ions) ,  to  the  skin  of  the  chest  and 
mamma?  principally ; 

Posterior  branches  [rami  posteriores) ,  to  the  skin  over  the  scap- 
ular and  lower  dorsal  regions. 

The  first  intercostal  nerve  (u.  intercostalis)  is  not  dis- 
tributed to  the  skin,  but  crosses  the  axilla  under  the  name  of 
the  intercostohumeral  nerve;  it  joins  the  brachial  plexus.  The 
lower  six  dorsal  nerves  have  received  the  name  of  lower,  or 
abdominal  intercostal  nerves,  from  their  distribution.  The  last 
dorsal  one  is  of  large  size,  and  gives  off  a  branch,  the  dorsilum- 
bar  nerve,  to  join  the  lumbar  plexus. 

Lumbab  Xerves  (tin.  lumhales). — The  posterior  (rami 
posteriores)  divisions  of  the  lumbar  nerves  have  the  same  dis- 
tribution as  the  other  spinal  nerves.  The  anterior  divisions  of 
the  upper  four  lumbar  nerves  unite  to  form  the  lumbar  plexus. 
The  fifth,  with  a  branch  from  the  fourth,  joins  the  sacral  nerves 
to  form  the  lumbosacral  cord. 

The  lumbar  plexus  (plexus  lumbdlis)  is  formed  by  the 
communicating  loops  from  the  anterior  branches  of  the  first  four 
lumbar  nerves  and  a  branch  from  the  last  dorsal. 

Its  branches  are: — 

1.  Iliohypogastric  (n.  iliohypogastric  us) ,  divides  into  two 
branches : — 

(a)  Iliac  branch  {ramus  cutancus  lateralis),  supplies  the  skin  of 
the  gluteal  region  and  the  oblique  muscles  of  the  abdomen; 

(6)  Hypogastric  braneli  (ramus  cutancus  anterior),  supplies  the 
skin  of  the  hypogastric  region  and  the  oblique  muscles. 

2.  Ilioinguinal  (a.  ilioinguinalis) ,  supplies  the  skin  of  the 
inner  and  upper  part  of  the  thigh,  the  scrotum,  and  labium  (in 
Female). 

3.  Genitocrural  (//.  genitofemoralis) ,  passes  through  the 
psoas  muscle  and  divides  into  two  branches: — 

"1  Genital  braneli  (//.  s/><  riniit  icus  extern  us  I .  follows  the  sper- 
matic cord  to  supply  the  cremaster  muscle;  in  female]  supplies  round 
ligamen! ; 

(0)  Crural  branch  in.  I  umboi  ngui  nalis ) ,  descends  m  the  sheath 
of  the  femoral  vessels  to  supply  the  skin  in  front  of  the  thigh. 

1.  External  cutaneous  (n.  cutaneus  femoris  lateralis) 
emerges  below  the  anterior  superior  spine  of  ilium  and  divides 
into: — 

('/i   Anterior  braneli,  i<>  skin  of  outer  and  fronl  aspect  of  thigh; 
(6)   Posterior  branch,  to  skin  of  outer  and  back  aspect  of  thigh. 


340  HUMAN    ANATOMY. 

5.  Obturator  (n.  obturatorius) ,  follows  the  brim  and  outer 
wall  of  pelvis  to  foramen  (obturator),  which  it  pierces  to  enter 
thigh. 

(a)  Anterior  branch  (ramus  anterior),  supplies  the  femoral 
artery; 

(b)  Posterior  branch  (ram-us  posterior),  supplies  the  adductor 
muscles; 

(c)  Articular  branch,  supplies  the  synovial  membrane  of  knee 
joint. 

6.  Accessory  obturator  (n.  obturatorius  accessorius) ,  sends 
a  branch  to  the  hip  joint  and  one  to  join  the  anterior  branch 
of  the  obturator  nerve. 

7.  Anterior  crural  (n.  femoralis),  the  largest  branch  of  the 
lumbar  plexus,  descends  through  the  psoas  muscle,  beneath 
Poupart's  ligament,  into  the  thigh,  where  it  divides  into  an 
anterior  or  cutaneous  branch,  and  a  posterior  or  muscular 
branch.  It  supplies  all  the  muscles  and  the  front  of  the  thigh, 
excepting  the  tensor  vagina?  femoris,  gives  branches  to  the  knee, 
and  supplies  the  skin  of  the  inner  side  in  front  of  the  thigh, 
and  to  the  leg  and  foot.  Its  branches  from  the  anterior 
division  are : — 

(a)  Middle  cutaneous,  to  sartorius  muscle  and  skin  of  front  of 
thigh ; 

( b )  Internal  cutaneous,  supplies  the  skin  in  the  inner  aspect  of 
the  leg; 

(c)  Long  saphenous  (n.  saphenus) ,  or  internal  saphenous,  passes 
through  Hunter's  canal,  accompanies  the  internal  saphenous  vein,  to 
supply  the  skin  of  the  inner  side  of  the  foot. 

From  the  posterior  division : — 

(a)  Muscular,  to  the  muscles  of  the  anterior  and  lateral  aspects 
of  the  thigh; 

(b)  Auricular,  to  the  knee  joint. 

The  sacral  nerves  (nn.  sacrales),  five  in  number,  divide 
into  anterior  and  posterior  nerves.  The  upper  four  sacral 
nerves,  with  the  fifth  lumbar,  and  a  filament  from  the  fourth, 
(the  latter  two  forming  the  lumbosacral  cord)  together  make  the 
sacral  plexus  (plexus  sacraUs).  It  lies  upon  the  anterior  sur- 
face of  the  pyriformis  muscle,  and  is  separated  from  the  viscera, 
the  sciatic  and  pudic  branches  of  the  internal  iliac  artery  by 
the  pelvic  fascia.     Its  branches  are: — 

1.  Muscular  (rami  muscular es) ,  supply  the  obturators, 
gemelli,  quadratus  femoris  and  pyriformis. 

2.  Superior  gluteal  (n.  glutozus  superior),  supplies  the 
glutei  muscles  and  tensor  vaginas  femoris. 


THE  NERVOUS  SYSTEM.  341 

3.  Pudic  (n.  pudendus),  accompanies  the  internal  pudic 
artery,  passing  out  of  the  great  sacrosciatic  foramen,  around 
the  spine  of  the  ischium  to  re-enter  the  lesser  sacrosciatic  fora- 
men.    It  gives  off: — 

(a)  Inferior  hemorrhoidal  (n.  hcemorrhoidalis  inferior),  supplies 
the  skin  of  the  anus ; 

(b)  Perineal  (n.  perinei) ,  follows  the  course  of  the  superficial 
perineal  artery  to  supply  the  perineal  structures  generally; 

(c)  Dorsal  nerve  of  the  penis  (to.  dorsalis  penis),  follows  the 
course  of  the  corresponding  artery  to  supply  the  skin  of  the  glans, 
prepuce  and  penis  generally. 

4.  Small  sciatic  (n.  cutaneus  femoris  posterior),  supplies 
the  skin  of  the  thigh,  leg,  perineum  and  the  gluteus  maximus 
muscle.    Its  branches  are: — 

(a)  Inferior  gluteal,  to  the  gluteus  maximus; 

(b)  Internal  cutaneous  branches  (toto.  cluniuin  inferiores  laterales), 
to  the  skin  of  the  inner  and  upper  part  of  the  thigh,  and  one  branch, 
the  inferior  pudendal,  supplies  the  skin  of  the  scrotum  in  the  male  and 
labium  in  the  female; 

(c)  Ascending  cutaneous  branches  supply  the  skin  over  the  gluteus 
maximus. 

5.  The  great  sciatic  nerve  (n.  isckiadicus) ,  the  largest  in 
the  body,  passes  out  of  the  great  sacrosciatic  foramen,  and 
descends  between  the  tuberosity  of  the  ischium  and  the  great 
trochanter  to  the  lower  third  of  the  thigh,  where  it  divides  into 
the  internal  and  external  popliteal.     It  gives  off: — 

(a)  Muscular  branches  (rami  musculares) ,  to  the  muscles  on  the 
inner  and  posterior  aspect  of  the  thigh ; 

(b)  Articular  branches,  to  the  hip  joint. 

The  internal  popliteal  (n.  tibialis),  descends  through  the 
popliteal  space  to  the  arch  of  the  soleus  muscle,  where  it 
becomes  the  posterior  tibial.    It  gives  off: — 

(a)    Articular  branches    (rami  articulares) ,  to  knee  joint; 
(6)    Muscular  branches    (rami  musculares),  to  the  muscles  on  the 
posterior  aspect  of  the  leg; 

(c)  Kxicrnal,  or  short  saphenous  nerve  (n.  suraUs),  passes  be- 
tween the  two  heads  of  the  gastrocnemius  muscle,  and  descends  the  leg. 
receiving  the  comnxunicans  peronei  branch  from  the  external  popliteal, 
around  the  outer  malleolus  to  supply  the  skin  of  the  outer  side  of  the 
foot. 

The  'posterior  tibial  nerve  descends  the  leg  in  company  with 
the  posterior  tioial  vessels  to  below  Hie  inner  ankle,  where  it 
divides  into  the  external  and  internal  plantar  nerves.     It  gives 

oil':— 


342  HUMAN   ANATOMY. 

1.  Muscular  branches  (rami  musculares) ,  to  the  deep  muscles  of 
the  calf; 

2.  Internal  cancaneal  (rami  aalctmei  mediates),  supplies  the  skin 
on  the  inner  side  of  the  sole  and  heel; 

3.  Articular  branch,  to  ankle  joint. 

The  internal  plantar  (n.  plantaris  medialis)  accompanies 
the  corresponding  artery  to  the  inner  side  of  the  foot  and  gives 
off:— 

1.  Cutaneous  branches; 

2.  Muscular  branches; 

3.  Articular  branches; 

4.  Four  digital  branches,  supplying  both  sides  of  the  first  three  toes 
and  the  inner  side  of  the  fourth. 

The  external  plantar  (n.  plantaris  lateralis)  supplies  by  a 
superficial  branch  the  outer  side  of  the  fourth  and  both  sides 
of  the  fifth  toes,  and  gives  off  a  deep,  or  muscular,  branch. 

The  external  popliteal  or  peroneal  nerve  (n.  peronceus  com- 
munis) descends  to  the  inner  side  of  the  biceps  tendon,  pierces 
the  peroneus  longus  about  one  inch  below  the  head,  and  divides 
into  the  anterior  tibial  and  musculocutaneous.     It  gives  off: — 

1.  Articular  branches    (rami  articulares) ,  to  knee  joint; 

2.  Cutaneous  branchesi  (n.  cutaneus  surce  lateralis),  one  of  which 
is  the  communicans  peronei  (ramus  anastomoticus  peronceus  or  com- 
municans  fibularis) ,  which  joins  the  short  saphenous. 

The  anterior  tibial  (n.  perona?us  profundus)  accompanies 
the  corresponding  artery  on  its  outer  side  to  the  ankle,  where, 
after  aivingr  off  an  articular  branch,  it  divides  into: — 

1.  External  or  tarsal  branch,  to  the  tarsal  and  metatarsal  joints, 
and 

2.  Internal,  to  the  dorsal  adjoining  sides  of  the  great  and  second 
toes. 

The  musculocutaneous  (n.  peronceus  superficialis)  gives 
off:— 

1.  Internal  branches,  (n.  cutaneus  dorsaUs  medialis),  supply  skin 
of  inner  side  of  foot  and  ankle,  and  inner  side  of  great  toe; 

2.  External  branch  (n.  cutaneus  dorsalis  intermedium) ,  to  the  dor- 
sum of  the  adjacent  sides  of  the  second,  third,  fourth  and  fifth  toes. 


/* 


Fig.  123. 
Sacral  plexus   and   branches. 


s 


First 

cervical  < 
nerve, 


Second 
cervical 
nerve 


Third 

cervical  - 

nerve, 


Fourth 

to 
eighth  ■{ 
cervical 
nerves, 


THE    XERVOIS    SYSTEM.  343 

Table   of   the   Spinal   Nerves. 

Complexus,  recti  and  obliqui  muscles. 


Posterior 

d  his  ion 

1  suboccipital) 


Anterior 

division 

(occipital), 


Posterior 
division, 


Anterior 
division, 


Posterior 
divison, 


Anterior 
divison. 


Posterior 
divisions, 


Unites  with  the  second  cervical  nerve, 
and  supplies  the  anterior  recti  and 
rectus  lateralis  muscles. 

External      ">  Splenitis,     complexus,     tra- 
branch,       /      cheloinastoid  muscles. 

,  ,'  !  ^Yith     branch     from     third 

branch,        i  .     .  ,.  ,. 

(great        '      cervical,      supplies      the 

occipital),     j       skin  of  the  scalP- 

f  Small  occipital, 

j  Branch  to  superficial   cervical, 

I  Branch  to  great  auricular, 

^  Branch  to  eommunicans  noni. 


f  External  ~]  0     , 

]  _    and  [Splenius 

}  internal  < 

[_  branches, 


semispinals, 
complexus,    trachelomas- 

toid  muscles. 


Branches  to  form  the  great  auricular, 
superficial  cervical,  and  communican- 
tes  minor. 


Internal 
branc 


11a  1       \  Miisclea  of  the  side  of  the 
'foes,      f      neck. 


sternal      ") 
'anches,      / 


External 
bm 


Skin     and     larger    muscles 
of  the  neck. 


[  Branch    to  phrenic, 

Anterior  division]  Branches      to      the      trapezius,      scalenus 

j  medius,    levator    anguli    scapulae    mus- 

I  cles. 


of   fourth, 


Anterior 

divisions, 

fifth  to  eighth, 


,     ,  ,  (    Superficial 

Cervical  plexus, 1  J. 


branches, 


Unite  with  the  first  dorsal  nerve  to  form 
the  brachial  plexus. 

(  Superficialis  colli, 

Ascending.      -  Auricularis  magnus, 
(  <  Occipitalis    minor. 

Descending.       Supraclavicular. 


1  Permed  by  the  anterior  divisions  of  the  first  to  the   fourth  cer- 
vical nerves, 


344 


HUMAN    ANATOMY. 


Table  of  the  Spinal   Nerves.— (Continued.) 


Cervical    plexus  f 
( continued ) ,      \ 


Deep 
branches,  \ 


f  Internal    set, 
I 


Brachial  plexus,1  < 


Above 

the 
clavicle, 


Below 

the 
clavicle, 


Three  sub- 
scapular, 


Circum- 
flex, 


Musculo- 
cutaneous, 


External   set, 

Communi- 
cating, 

Muscular, 

Posterior 
thoracic, 


Supra- 
scapular, 


Anterior 
thoracic, 


Communicating, 

Muscular,  <  , 

t  muscles. 

Phrenic, 

Communicans  noni. 

Muscular, 
Communicating. 


To  phrenic. 

Scaleni,     rhomboidei,     lon- 
gus  colli,  subclavius. 

Serratus  magnus. 
(  External    respiratory 
nerve  of  Bell.) 

Shoulder   joint  and   supra- 
spinatus    muscle. 

External 
branch, 


Internal 
branch, 


Upper, 
Lower, 
Middle, 


Upper, 
Lower, 


Anterior 
branch, 


f      Pectoralis 
\  major. 

f  Pectoralis 
J  minor, 

i,  Pectoralis 

(  major. 

[     Subscapular 
\         muscle. 

Teres  major. 

f      Latissimus 
1  dorsi. 

f       Shoulder 
j      joint,    and 
\     muscles  and 
[  skin  about  it. 

f     Integument 
j  of  palmar  sur- 
i,      face  of  the 
j  wrist. 


f  Integument 
Posterior  j  of  dorsal  sur- 
branch,      \  face  of  the 
|  wrist. 

i  Formed  by  the  anterior  branches  of  four  lower  cervical  and  first 
dorsal  nerves. 


THE    NERVOUS    SYSTEM. 


345 


Table  of  the  Spinal    Nkkvks.— (Continued.) 


Brachial 

plexus, 

below  the 

clavicle 
contirid, 


Internal 


f    Anterior    ]  Integument  of 
a  nd 


internal         j  auu.  inner  side  of 

cutaneous,      1     posterior     f       the  arm. 
branches,    J 

Lesser  internal  [integument  of  the  inner 
cutaneous       <      sjcje  0f  h,a  arrrL 
(Wrisberg's),    [ 


Median,    - 


f         Muscular, 


Anterior 

interosseous, 

Palmar 

cutaneous, 

Branch   to 

the  musclesi  of 

the  thumb, 

Digital 

branches, 


1 


(  Superficial  anterior  mus- 
J  cles,  except  flexor  carpi 
(      ulnaris. 

fDeep  anterior  muscles,  ex- 
cept the  inner  half  of 
flexor  profundus  digi- 
torum. 

J  Ball  of  thumb  and  palmar 
\      surface  of  the  hand. 

Opponens,  outer  head  of 
small  flexor  and  ab- 
ductor. 

fBoth  sides  of  thumb,  in- 
:  dex  and  middle  fingers 
i  and  radial  side  of  ring 
[       finger. 


Articular,         j  (Elbow) 


Ulnar, 
in  forearm,' 


f  Inner  half  of   deep   flexors 
Muscular,         j      and  flexor  carpi  ulnaris. 

Cutaneous,        {  Skin   of   the   palm. 

(Both  sides  of  little  finger 
|  and  ulnar  side  of  ring 
[      finger. 


Dorsal 

cutaneous, 


Articular,         {  (Wrist). 


I  In. ir, 
in   hand, 


Superficial 

palmar, 


Deep 
palmar, 


f  Skin  of  both  sides  of  little 
j        linger,  ulnar  side  of  ring 
\       finger      and       palmaria 
brevia  muscle. 

f  luicrossei   lumbricales,  ad 
:      ductor      pollicis,      inner 

\       head      of      flexor     brevis 
pollicis. 


34G 


HUMAN    ANATOMY. 


Table  of  the  Spinal   Nerves. — (Continued.) 


Brachial 

plexus, 

below  the 

clavicle, 

cont'd, 


Musculo- 
spiral, 


Dorsal 

nerves, 


Posterior 
divisions, 


Anterior 
divisons,i 


Lumbar 
nerves, 


Posterior 
divisions, 


Anterior 
_  divisions,     \ 


f  Supinator  longus,  extensor 
Muscular  j  carpi  radialis  longior,  tri- 
branches,        i       ceps,     anconeus,     brachialis 

[      anticus. 

f  Supplies    adjoining    sides     of 
_    ,.  ,  j       thumb     and     index     finger, 

Kadial,         -j       index    and    middlej    middla 

[       and  ring  fingers. 

(Inner  side  of  arm,  elbow, 
radial  side  of  forearm  and 
wrist. 

f  Posterior  brachial  and  radial 
Posterior       j       muscles,    except   those    sup- 
interosseous,    i       plied    by    ulnar     (muscular 
[       branches ) . 


External 
branches, 

Internal 
branches, 


Upper  six 

( thoracic 

intercostals ) , 


^Muscles  and  skin  of  the  back. 


First  intercostal  crosses  the 
axilla  to  join  the  lesser  in- 
ternal cutaneous  ( Wris- 
berg's ) . 


Lateral 
cutane-  ■< 
ous, 


Ante- 
rior, 


Poste- 
rior, 


f    Skin  of 
■j  chest  and 
(.  mamma?. 

Skin  over 
scapula 

and  lower 
dorsal 
region. 


r. 


Lower  six  i  The  ]agt  dorgal   gWes  off  the 

(thoracico-  ^       dorsilumbar    to    the    quad- 

abdominal  ,       ratus   lumborum  muscle, 

intercostals ) ,  [_ 


External 
branches, 

Internal 
branches, 


I  Muscles    of 
back. 


the    skin    of    the 


f  The  four  upper  unite  to  form  the  lumbar 
plexus.  The  fifth,  with  a  branch  from  the 
fourth,  joins  the  sacral  nerves  to  form  the 
lumbosacral  cord. 


I 


l  To  the  walls  of  chest  and  abdomen. 


THE    NERVOUS    SYSTEM. 


347 


Table  of  the   Spinal    Nerves. — (Continued.) 


Ilio- 
hypogastric, 


Lumbar 
plexus. 


f  Skin    of    gluteal     region,    ob- 
lliac,         I      lique  muscles   of  abdomen. 


Hypo-         I  Skin     of     hypogastric     region 
gastric,        I 


and  oblique  muscles. 


Ilio- 
inguinal, 


Genito- 
crural, 


External 
cutaneous, 


(  Skin  of  inner  and  upper  part  of  thigh,  scro- 
ll     turn,  labium   (in  female). 

f  Cremaster  muscle,  round  liga- 
Genital,      |      ment   (in  femaie). 


Posterior, 

Anterior, 

Obturator,     \    Posterior, 

Articular, 


Crural,       {  Skin  of  front  of  thigh. 

(  Skin  of  outer  front  aspect  of 
Anterior,      |      thigh 

Skin  of  outer  back  aspect  of 


/  Skin  of 

\    thigh. 

I  Femoral  artery. 
<  Adductor  muscles. 

Is" 


Synovial    membrane    of    knee- 
joint. 

Accessory        f  Branch     to    hip- joint,     branch     to     anterior 
obturator,      \     branch  of  obturator  nerve. 

f     Sartorius 
Middle     j        muscle, 
cutaneous,   \        skin   of 

[_ thigh  (ant,). 

f      Skin   of 
Internal    j  inner 

cutaneous,  1      aspect  of 
leg. 


Anterior, 
division, 


Anterior 

crural, 


Skin  of 

-,  inner  side  of 
saphenous,  j  foot> 


Lone 


Posterior, 
division] 


f  Muscles 

j  of  the  an- 

_  _,        .  terior   and 

f    Muscular.  J  ];it|,n|| 

aspect  of 

J                          [  thigh. 

[_  Articular,  j  Knee  joint. 


348 


HUMAN    ANATOMY. 


Table  of  the  Spinal   Nerves— (Continued. )_ 


Sacral 
nerves, 


!   Posterior 
I   divisions, 


External 

and  internal 

branches, 


Muscles     and     skin     of     the 
back. 


|   Anterior    f     The  four  upper  joining  with  the   lumbosacral 
[  divisions,   \         cord  form  the  sacral  plexus. 


Sacral 
plexus, 


Obturators,     gemelli,     quadratus     femoris     and 
Muscular,  |         piriformis. 

Superior   j     Qiu^ei  muscles  and  tensor  vaginae  femoris. 

Inferior  f  gkin  of  ^  anug 

rhoidal,       ( 


rineal  structures. 


hemor 
Pudic,     ■{  Perineal,  <  Peri 

<  Skin  of  the  penis. 

To  hip  joint. 

i  Gluteus  maximus. 


Dorsal   nerve  of 
the  penis, 


Articular 


{ 


Small 
sciatic, 


Inferior 
gluteal, 


Great 
sciatic. 


Internal 
cutaneous, 


Ascending 
cutaneous, 

Articular, 
Muscular, 


f  Branch  to  skin  of  inner  and 
upper  part  of  thigh. 


H 


Inferior    pudendal,    skin    of 


scrotum,     labium     in     fe- 
^      male. 

I  Skin  over  gluteus  maximus. 

-J   Hip  joint. 

/  Muscles    of    inner    and    pos- 
\       terior  part  of  thigh. 


Bifurcation,       { ^Sal,'    }   PoPliteaL 


Internal 
popliteal, 


Articular 
branches, 


To  knee  joint. 


Muscular  "1  To  muscles  of  the  posterior  aspect  of 

branches,  J      the  leg. 


THE    NERVOUS    SYSTEM. 


349 


Table  of   the   Spinal    Nerves. — (Continued.) 


Conmmnicans      \    skin  of  outer   side  of  the  foot 
poplitei,  j 


Internal 

popliteal 

[continued) 


Posterior  tibial 
(continuation), 


,  (  Deep    muscles    of    the 

Muscular,       j      c.{,f 


Plantai 

cutaneou 


Skin  of   inner   side  of 
sole  and  heel. 


:,  { 

Articular,       j  To  ankle  joint. 

j  Internal   plantar, 


Bifurca- 
tion, 1  External    plantar. 


Internal 


f  Cutaneous, 
Muscular, 


plantar,       \  Articular, 

'[_  Four  digital. 


External 
plantar, 


Supplies  the  outer 
side  of  the  fourth 
and  both  sides  of 
the  fifth  toes.  Mus- 
cular branch. 


External 

|H)pliteal    * 
(  peroneal), 


Articular,  j      To  knee  joint. 


Two 

cutaneous, 


Anterior 

tibial, 


M  usculo- 
cutaneous, 


Communieans  peronei. 


External 
or   tarsal 
branch,        J 


Internal 
branch. 


Internal 
branches, 


External 
branch, 


1    Tarsal     and    metatar- 
sal joints. 


f  Inner  and  dorsal,  ad- 
j  joining  sides  of 
\         great     and      second 


I  toes. 

<  To  skin  of   inner   side 

\  of  foot   and  ankle. 

f  To    dorsum    of    adja- 

J  cent    sides   of    third, 


fourth 

toes. 


and       fifth 


350  HUMAN    ANATOMY. 


THE     SYMPATHETIC     NERVOUS     SYSTEM. 

The  sympathetic  system  (sympatheticus) ,  like  the  cerebro- 
spinal axis,  is  double,  consisting  of  a  gangliated  cord  {truncus 
sympatheticus)  on  each  side,  extending  the  entire  length  of  the 
vertebral  column,  and  numerous  nerve  fibers,  both  communicat- 
ing, by  which  it  anastomoses  with  the  cerebrospinal  axis,  and 
distributory,  by  which  the  blood  vessels  and  viscera  are  supplied. 

Branches  of  the  gangliated  cords  .  ascend  through  the 
carotid  canal  to  communicate  with  the  ganglia  of  the  fifth 
"cranial  nerve,  and  also  with  each  other  through  the  ganglion  of 
Ribes,  situated  upon  the  anterior  communicating  artery.  They 
also  communicate  below  in  the  ganglion  impar  (ganglion  coccyg- 
eum  impar),  located  in  front  of  the  coccyx. 

The  ganglia  of  each  cord  correspond  very  nearly  in  posi- 
tion and  number  to  the  vertebra?,  except  in  the  cervical  region, 
where  there  are  but  three :  cervical  three,  dorsal  twelve,  lumbar 
four,  sacral  five. 

From  the  gangliated  cords  three  important  plexuses  are 
given  off — the  cardiac,  solar,  and  hypogastric — situated  in  the 
thoracic,  abdominal  and  pelvic  cavities,  respectively. 

Cranial  Ganglia — Ganglia  Connected  ivitli  the  Fifth  Cranial 
Nerve. — Besides  the  Gasserian  ganglion  upon  the  root  there  are 
four — ophthalmic,  sphenopalatine,  otic  and  submaxillary — each 
of  which  has  three  branches  of  communication  or  roots — motor, 
sensory  and  sympathetic — besides  several  branches  of  distribu- 
tion. 

The  ophthalmic,  or  ciliary  ganglion  (ganglion  ciliare),  is 
'  situated  in  the  orbit  between  the  external  rectus  muscle  and 
I   optic  nerve  upon  the  first  division  of  the  fifth  cranial  nerve. 

Its  sensory  root  (radix  longa  ganglii  ciliaris)  is  from  the 
nasal  branch  of  ophthalmic,  motor  root  (radix  brevis  ganglii 
ciliaris)  from  the  motor  oculi  or  third,  and  sympathetic  from 
the  cavernous  plexus. 

Its  branches  are  the  short  ciliary  nerves  (vide  Eye). 

Sphenopalatine,  or  Meckel's  (ganglion  sphenopalatinum) , 
the  largest,  is  situated  in  the  sphenomaxillary  fossa  upon  the 
superior  maxillary,  or  second  division  of  the  fifth. 

Its  sensory  root  is  derived  from  the  superior  maxillary,  its 
motor  root,  from  the  facial,  through  means  of  the  Vidian,  and 
its  sympathetic  from  the  carotid  plexus.     Its  branches  are : — 

1.  Ascending  (rami  orbitales)  ; 


}  -Irterv 


To*UtJt*\ 

7c  TrTnptiftiehra/H'Ji 
■jfolos. 


From  l**£trrz£aLi  \W*-* 
fn  n 

J>t  tm  3  ~?i'.r> .-.  j/.  I  'cm  >. 


Ophthalmia -rtasit.  It 
trre 


V^jryi  Superficial  flrf/wKz//rv/*J'asia/A*rrr 


i  /reuniting  fc-r*0m/4r&/ 


,         .tt./  its  6rajt&M  . 


..!>,.;     - 

RnmSfJlmtal  Xern  ^, 

Srvmf^Jij'.a/  A'tri't    "~~^*J 

A^-yi.-reponyir,,!  lr,iri,-Acl,  .,r' 


.iW..*™*,^     ^ 

.^ 

»mVtlu,„!,„r.V<r„  —»= 

* 

•ms*[ma*rjam  -^^ 

A 

— — ^A 

^>v, 

/'" 

JW^Kn    £^& 

From.  CoccfgealXerrx 

Fig.  124. 
The  sympathetic    system. 


THE    NERVOUS    SYSTEM.  35] 

f  Anterior,   or   large   palatine    (».   pilar 
Unas  and  rior  1 . 
2.  Descending,      or      pala-  !    Middle,  or  external  palatine    (».  pala- 
tine    [mi.    palatini  \ ,   j         /i'hi/s   melius), 

\    Posterior,  or  small  palatine    (».  pato- 
is      tinus  posterior) , 


f  Pos 
{  Na 


Posterior  superior  nasal  (rami  namks 
3.  Internal,  -{        posteriores  superiores), 

Fasopalatine   (n.  nasopaiat&nus) , 


4.  Posterior, 


Vidian    (>i.  canalis  pterygoidea), 
Large  superficial  petrosal   (n.  petrosus 

supcrficialis  major) , 
Deep  petrosal  (n.  petrosus  profundus), 
Pharyngeal  branch. 


The  Vidian  nerve  (n.  canalis  pterygoidea)  passes  from  the 
baj?k  part  of  Meckel's  ganglion  through  the  foramen  laeerum 
medium,  where  it  divides  into  the  large  superficial  and  deep 
petrosal  nerves.  Jt  gives  off  the  upper  posterior  nasal  branches 
to  the  mucous  membrane  of  septum,  orifice  of  Eustachian  tube. 
and  roof  of  the  nose.  Or,  more  correctly,  the  Vidian  is  formed 
by  the  union  of  the  great  petrosal  (large  superficial  petrosal) 
from  the  facial  and  the  large  deep  petrosal  from  the  carotid 
sympathetic,  runs  forward  through  the  Vidian  canal,  and  joins 
the  sphenopalatine  ganglion  (Meckel's).  In  this  description, 
the  nerves  given  off  to  the  nasal  mucous  membrane  must  be 
considered  branches  from  the  ganglion  inclosed  in  the  same 
sheath. 

The  large  superficial  petrosal  branch  (n.  petrosus  super- 
firiahs  major)  enters  the  cranium  through  the  foramen  laeerum 
medium,  passes  beneath  the  dura  mater  and  Gasserian  ganglion, 
enters  the  hiatus  Fallopii,  receives  a  branch  from  the  tympanic 
branch  of  the  glossopharyngeal  (Jacobson's),  and  through  the 
aqueductus  Fallopii  to  terminate  in  the  geniculate  ganglion  of 
the  facial  nerve. 

The  large  deep  petrosal  branch  (n.  petrosus  profundus) 
crosses  the  foramen  Laeerum  medium  to  the  carotid  canal,  where 
it  joins  the  carotid  plexus  of  the  sympathetic. 

The  pharyngeal  or  pterygopalatine  nerve  descends  from  the 
back  part  of  the  ganglion  through  the  pterygopalatine  canal,  to 
supply  the  upper  part  of  the  pharynx. 

Besides  the  Vidian  and  its  branches  there  are  two  other 

petrosal    nerves    (vide    Facial    Sfvw),    the    small    and    external 

petrosaL 


352  HUMAN    ANATOMY. 

The  small  petrosal  connects  the  geniculate  ganglion  of  the 
facial;,  within  the  aqueductus  Fallopii,  with  the  otic  ganglion. 

The  external  petrosal  connects  the  geniculate  ganglion  of 
the  facial,  within  the  same  canal,  with  the  sympathetic  plexus 
of  the  middle  meningeal  plexus. 

The  otic  or  Arnold's  ganglion  (ganglion  oticum)  is  placed 
below  the  foramen  ovale  upon  the  inferior  maxillary  nerve,  or 
third  division  of  the  fifth. 

Its  sensory  root  is  derived  from  the  auriculotemporal 
branch  of  the  inferior  maxillary ;  the  motor  root,  from  the  inter- 
nal pterygoid  branch  of  the  same;  the  sympathetic  root,,  from 
the  plexus  on  the  middle  meningeal  artery.  Branches  are  dis- 
tributed to  the  tensor  palati  (n.  tensoris  veil  palatini)  and  ten- 
sor tympani  (n.  tensoris  tympani)  muscles. 

The  submaxillary  ganglion  (ganglion  submaxillare)  is 
placed  above  the  deep  portion  of  the  submaxillary  gland. 

Its  sensory  root  is  derived  from  lingual  branch  of  inferior 
maxillary;  its  motor  root,  from  the  facial  nerve  through  a 
branch  of  the  chorda  tympani;  and  its  sympathetic,  from  the 
plexus  of  the  facial  artery. 

Besides  these  ganglia,  situated  upon  branches  of  the  tri- 
facial nerve,  the  following  are  found  within  the  cavity  of  the 
cranium : — 

Ganglion  of  Ribes,  on  the  anterior  communicating  artery; 
Ganglion  of  Bidder,  on  the  middle  meningeal  artery; 
Ganglion  of  Laumonier,  on  the  internal  carotid  artery; 
Ganglion  of  Cloquet,  on  the  nasopalatine  nerve  in  the  incisor  fossa; 
Ganglion  of  Bochdaleck,  near  the  sphenopalatine  ganglion. 

Cervical  Ganglia. — The  cervical  ganglia  consist  of  three, — 
superior,  middle,  inferior, — of  which  the  superior  is  the  largest 
and  the  middle  the  smallest.  These  are  connected  above  with 
the  cranial  ganglia,  below  with  the  thoracic  ganglia,  and  com- 
municate with  each  other. 

The  superior  cervical  ganglion  (n,  caroticus  internus)  lies 
opposite  the  second  or  third  cervical  vertebra,  behind  the  inter- 
nal carotid  artery.  It  is  connected  with  the  middle  ganglion, 
the  upper  four  cervical,  and  tenth  and  twelfth  cranial  nerves, 
distributes  branches  to  the  carotid  (internal),  cavernous  (plexus 
cavernosus)  and  pharyngeal  plexuses,  and  gives  off  the  superior 
cardiac  nerve  to  the  cardiac  plexus  (plexus  caroticus  internus). 

The  middle  cervical  ganglion  (ganglion  cervical  medium) 
lies  upon  inferior  thyroid  artery,  opposite  fifth  cervical  vertebra. 
It  is  connected  with  the  upper  and  lower  ganglia  and  spinal 


THE    NERVOUS    SYSTEM.  353 

nerves,  and   gives  off  the  middle  cardiac  nerve    (n.  cardiacus 
medius)  to  cardiac  plexus. 

The  inferior  cervical  ganglion  (ganglion  cervicale  inferius) 
lies  internal  to  the  superior  intercostal  artery,  below  the  last 
cervical  vertebra.  It  is  connected  to  the  middle  ganglion,  first 
thoracic,  lower  cervical  nerves,  forms  the  vertebral  plexus,  and 
gives  off  the  inferior  cardiac  nerve  (n.  cardiacus  inferior)  to 
cardiac  plexus. 

Thoracic  ganglia  (pars  thoracalis)  lie  upon  the  heads  of 
the  ribs  on  each  side  of  the  vertebral  column.  They  are  con- 
nected with  the  inferior  cervical  ganglion  above,  the  lumbar 
ganglion  below,  the  dorsal  spinal  nerves  behind,  and  give  off 
internal  branches  divided  into  two  sets  of  six  each — -upper  and 
lower. 

internal  branches  from  upper  set  are  distributed  to  the 
pulmonary  and  aortic  plexuses  (plexus  aorticus  thoracalis),  and 
internal  branches  from  lower  set  unite  to  form  the  three  splanch- 
nic nerves — great  splanchnic  (n.  splanchnicus  major),  lesser 
Bplanchnic  (n.  splanchnicus  minor),  renal  splanchnic, — distrib- 
uted respectively  to  the  semilunar  ganglion,  renal  and  supra- 
renal plexuses,  and  to  renal  and  celiac  plexuses. 

The  lumbar  ganglia  (pars  lumbalis)  lie  along  inner  mar- 
gin of  the  psoas  muscle.  They  communicate  above  and  below 
with  the  other  ganglia  and  with  the  lumbar  spinal  nerves,  and 
give  off  internal  branches  which  form  the  hypogastric  plexus. 

The  sacral  ganglia  (pars  sacralis)  are  situated  internal  to 
the  anterior  sacral  foramina.  They  unite  below  in  front  of  the 
coccyx  iti  the  coccygeal  ganglion,  or  ganglion  impar.  They 
communicate  with  the  sacral  nerves,  join  the  pelvic  plexus,  and 
scud  branches  on  the  middle  sacral  artery. 

Cardiac  Plexus  (plexus  cardiacus). — The  cardiac  plexus. 
formed  from  the  superior,  middle  and  inferior  cardiac  nerves 
from  the  cervical  ganglia,  and  the  cardiac  branches  from  the 
pneumogastric  and  recurrent  laryngeal,  consists  of  two  portions 
— the  superficial  and  deep. 

The  superficial  cardiac  plexus,  situated  beneath  the  arch  of 
the  aorta,  is  formed  by  the  left  superior  cardiac  nerve  and  the 
left  inferior  cervical  cardiac  nerve,  and  contains  the  cardiac 
ganglion  of  Wrisberg  (ganglion  cardiacum  [Wrisbergi] ) .  It 
form-  part  of  the  anterior  coronary  plexus,  and  sends  branches 
to  the  left  anterior  pulmonary  plexus. 

Tin'  deep  cardiac  plexus  lies  between  the  arch  of  the  aorta 
and  trachea,  and  receives  all  the  cardie  nerves  except  the  two 
mentioned    above.      It    forms    part   of    the    anterior    coronary 

23 


354  HUMAN   ANATOMY. 

{plexus  coronarius  cordis  anterior)  and  posterior  coronary 
{plexus  coronarius  cordis  posterior)  plexuses. 

The  solar  plexus  {plexus  cceliacum),  or  "abdominal 
brain,"  consists  of  ganglia  and  a  network  of  nerve  branches, 
formed  chiefly  from  the  branches  of  the  two  great  splanchnic 
nerves  and  branches  from  the  right  pneumogastrie.  It  is  sit- 
uated between  the  aorta  and  the  crura  of  the  diaphragm  and 
the  stomach,  and  surrounds  the  superior  mesenteric  artery  and 
celiac  axis. 

Its  ganglia  are  two  crescentic  ganglionic  masses — the  semi- 
lunar ganglia  {ganglia  coeliaca) — the  largest  in  the  body — sit- 
uated in  front  of  the  crura  of  the  diaphragm.  They  are  com- 
posed of  small  ganglia  aggregated  together.  From  the  solar 
plexus  and  semilunar  ganglion  are  derived  numerous  branches 
which  are  distributed  as  plexuses  over  all  the  abdominal  arteries, 
as  follows: — 

Cceliac    {plexus  cceliacus) ,  Spermatic    (plexus   spermaticus) , 

Gastric     [plexus    gastricus     supe-  Aortic     (plexus    (tortious    abclomi- 

rior) ,  nalis) , 

Hepatic   (plexus  hepaticus) ,  Superior   mesenteric    (plexus  mes- 

Splenic    (plexus  lienalis),  entericus  superior), 

Phrenic    (plexus  phrenicus),  Inferior  mesenteric    (plexus     rnes- 

Suprarenal    (plexus  suprarenalis) ,  entericus  inferior), 

Renal  (plexus  renalis) ,  Ovarian   (plexus  arterke  ovaricce), 

The  hypogastric  plexus  {plexus  hypogastricum)  is  sit- 
uated below  the  bifurcation  of  the  aorta,  in  front  of  the  sacrum, 
and  is  formed  by  branches  from  the  lumbar  ganglia  and  aortic 
plexus.  It  divides  into  two  parts  which,  with  branches  from 
the  sacral  ganglia  and  nerves,  become  the  pelvic  plexuses. 

The  inferior  hypogastric  or  pelvic  plexus  on  each  side 
gives  off  the  following  branches : — 

Vaginal  plexus,  Inferior     hemorrhoidal      (plexus 

Tuemorrlioidalis  inferior) , 

(  Small       cavernous  "| 

nerves  (n.  oavernosus   j 

Prostatic      plexus/     penis  minor),  \ 

(plexus  prostaticus)  ,\   Large       cavernous   j         "        ' 

nerves  (n.  oavernosus   I 

(_    major ) ,  J 

Vesical  plexus    (plexus  vesicalis),      Uterine  plexus. 


ORGANS  OF  SPECIAL  SENSE. 


T 1 1  E    NOSE. 


The  nose  (organon  ol) 'actus),  the  special  organ  of  smell, 
consist*  of  two  parts, — the  external  prominence,  or  nose  proper, 
and  the  internal  cavities,  or  nasal  fossae. 


fc&-"NASAL 


SEPTA 
OF    S 


L  branch) 

UPERIOR      r 
ASAL  1 


Fig.  125. 

The  olfactory  nerves  and  nerves  of  common  sensation 
to  the  nose.     (Ei-kley.) 

The  nose  proper  is  made  up  of  a  cartilago-osseons  frame- 
work covered  with  muscles  (vide  Muscles)  and  skin,  and  lined 
with  mucous  membrane.  The  osseous  portion  is  formed  by  the 
margins  of  the  anterior  meatus  (vide  Osteology). 

The  cartilaginous  portion  consists  of  an  upper  (cartilago 
nasi   lateralis)    and    lower    lateral    cartilage    (cartilago    alaris 

major)   on  either  side,  and   the  nasal  septum  dividing  the  nasal 

cavity  into  two  nasal  fossae  durum  nasi). 

Vrtenes  are  from  nasal  branch  of  ophthalmic  and  infra- 
orbital, nasal  artery  From  superior  coronary,  and  branches  of 
the  lateralis  nasi. 

(355) 


356  HUMAN   ANATOMY. 

Veins  empty  into  the  ophthalmic  and  facial  veins. 

Nerves  from  infratrochlear,  infraorbital  and  facial. 

The  nasal  fossae  (cavum  nasi)  are  the  two  bony  cavities 
already  described  (vide  page  45).  They  are  lined  throughout 
with  mucous  membrane  (membrana  mucosa  nasi)  called 
Sclmeiclerian  membrane,  which  is  continuous  with  the  antrum 
of  Highmore,  frontal,  ethmoidal  and  sphenoidal  sinuses,  with 
the  conjunctiva  through  the  lachrymonasal  duct,  with  the 
pharynx  through  the  posterior  nares  (choanal),  and  with  cavity 
of  the  tympanum  through  the  Eustachian  tube.  Its  epithelium 
is  columnar,  ciliated  in  the  lower  part  and  in  the.  sinuses,  and  is 
columnar,  but  not  ciliated,  in  the  membrane  to  which  the  olfac- 
tory nerve  is  distributed. 

Arteries  are  anterior  and  posterior  ethmoidal  from  the 
ophthalmic  to  the  roof,  frontal  and  ethmoidal  sinuses,  spheno- 
palatine from  the  internal  maxillary  to  the  mucous  membrane 
of  the  spongy  bones,  septum,  and  meatuses,  and  alveolar  from 
the  internal  maxillary  to  the  antrum. 

Veins  empty  into  facial,  ophthalmic,  and  beginning  of 
great  longitudinal  sinus. 

Nerves  are : — 

Olfactory,  or  first  cranial,  the  special  nerve  of  smell,  is  dis- 
tributed over  the  upper  third  of  the  septum  and  superior  turbi- 
nated bones. 

Anterior  dental  branch  of  superior  maxillary  to  the  inferior 
turbinated  bone  and  inferior  meatus. 

Nasal  branch  of  ophthalmic,  to  the  outer  walls  and  septum. 
Besides  these,  the  sphenopalatine  ganglion,  the  Vidian,  the  supe- 
rior nasal  branch,  nasopalatine  and  anterior  palatine  also  send 
branches  to  the  parts. 

THE    EYE. 

The  organs  of  sight  comprise  the  eyeballs  (bulbus  oculi) 
and  their  appendages  and  the  optic  nerves. 

The  eye  is  a  spherical  organ,  situated  in  the  anterior  part 
of  the  skull,  protected  in  front  by  several  appendages,  acted 
upon  by  muscles,  and  supplied  by  blood  vessels  and  nerves. 

Within  the  orbit  it  rests  upon  a  bed  of  fat,  from  which  it 
is  separated  by  a  membranous  sac — the  capsule  of  Tenon  (fascia 
bulbi  [Tenoni]). 

It  presents  the  following : — 

Diameters. — Anteroposterior,  in  the  adult,  .950  inch; 
transverse,  .925;  vertical,  .915;  oblique,  .9-13. 


ORGANS  OF  SPECIAL  SENSE. 


357 


Fig.  126. 


Nasal  meatuses  and  accessory  cavities.  1,  right  termination  of  the 
left  frontal  sinus;  2,  right  frontal  sinus;  3,  probe  extending  from  the 
right  frontal  sinus  through  the  infundibulum  into  the  right  nasal 
fossa;  4,  ethmoid  cells;  5,  large  opening  into  the  maxillary  sinus;  6, 
anterior  antrum  of  the  sphenoid  bone;  7,  posterior  sphenoid  antrum; 
v.  middle  nasal  meatus;  9,  Inferior  meatus;  i<»,  Inferior  turbinated 
bone;  11,  probe  extending  through  the  nasal  dint.     (Bishop.) 


558 


HUMAN    ANATOMY. 


Anterior  and  posterior  poles  are  the  geometric  centers  of 
the  cornea  and  fundus  respectively. 

Optic  axis  (axis  optica)  is  a  straight  line  passing  through 
the  cornea  and  posterior  pole  of  the  eye. 

Line  of  vision,  or  visual  axis  (linea  visus) ,  is  an  imaginary 
line  which  connects  the  point  of  fixation  with  the  fovea  cen- 


81du8  front, 
yifttnltia  papyr.  oss.  ethmoid. 


Foramina  ethmoid, 
?roc.  orbit,  oss.  palat. 
Corpus  oss.  sphenoid. 


For.  optic 
ffosura  orbit,  eup. 
Sella  turcica     \ 


Spina  trochlear.  j 

Bars  orbit,  oss.  front.  ! 


Fossa  sacci  lacrim. 

Oa  nasale 


'acies  orbit.  maxQl. 
Froo.  uncin.  oss. 
ethmoid. 
Froo.  ethmoid,  concha* 

nasal,  inf. 

Proo.  max  ill.  conchae 

nasal,  inf. 


canal,  palat. 


Sinus  maxiliarial 
PaTs  perpondic.  oss.  palat. 


Fig.  127. 
Inner  wall  of  orbit  and  adjacent  parts.     (His.)     (Ball.) 


tralis,  through  the  nodal  point,  usually  to  the  outer  side  of  the 
center  of  the  pupil.  It  forms  with,  the  optic  axis  as  it  cuts  the 
cornea,  the  visual  angle — an  angle  of  from  3°  to  7°. 

Nodal  point  is  an  imaginary  point — the  center  of  curvature 
of  the  refracting  media — where  all  the  luminous  rays  pass  with- 
out deviation. 

Equatorial  plane,  an  imaginary  plane  passing  through  the 
center  of  the  eyeball  at  right  angles  to  the  optic  axis,  dividing 
the  globe  into  two  hemispheres — the  anterior  and  posterior. 


ORGANS  OF  SPECIAL  SENSE. 


359 


Equator  is  the  line  upon  the  surface  of  the  glohe  where  the 
equatorial  plane  cuts  it. 

Meridional  planes  are  imaginary  anteroposterior  planes  co- 
inciding with  the  axis. 

Meridians  are  the  lines  upon  the  surface  where  these  merid- 
ional planes  cut  it. 

The  capsule  of  Tenon,  tunica  vaginalis  oculi  (fascia 
oculi  [Tenoni]),  is  a  fascia  between  the  eyeball  and  the  walls 
of  the  orbit,  isolating  the  eyeball  and  allowing  free  movement. 


Fig.  128. 

Horizontal  section  of  right  orbit.  1,  Horner's  muscle;  2,  septum  or- 
bitale;  '.',,  fibers  of  the  orbicularis  palpebrarum  muscle;  4,  tarsal  plate; 
5,  conjunctival  sac;  6,  outer  palpebral  ligament;  7,  temporal  muscle; 
S,  wall  of  the  orbit;  9,  external  rectus  muscle;  10,  orbital  fat;  11,  optic 
nerve;  12,  internal  rectus  muscle;  13,  inner  check  ligament;  14,  inner 
wall  of  the  orbit;  15,  attachment  of  the  capsule  of  Tenon  (1G)  to  the 
conjunctiva;  17,  Tenon's  space;  18,  outer  check  ligament;  19,  lachrymal 
gland;  20,  ciliary  process;   21,  iris.     (Ball  after  Gerlach.) 

It    i-  continuous  in    front  with  the  subconjunctival  connective 

tiss  iw.  and  behind  with  the  dura  mater,  through  the  sphenoidal 

fissure  and  optic  foramen,  and  consists  of  two  layers — a  visceral 

investing  the  posterior  portion  of  the  eyeball,  and  a  parietal 

lining  the  cushion  of  fat  on  which  the  eye  rests. 

The  inner  aspect  is  lined  with  flattened  endothelial  cells, 

and  incloses  a  lymph  Bpace  communicating  with  subdural  and 

subarachnoidean  lymph  spaces  of  the  optic  nerve  sheath.    It  sup- 


360 


HUMAN    ANATOMY. 


ports  the  lachrymal  gland,  is  strengthened  by  numerous  fibrous 
bands,  and  is  pierced  by  the  ocular  muscles,  inclosing  them  in 
imperfect  sheaths. 

The  capsule  of  Bonnet  is  the  name  given  to  the  portion 
posterior  to  the  passage  of  the  tendons,  and 

The  capsule  of  Tenon  is  then  applied  to  the  anterior  socket- 
like half. 

The  eyeball  (biilbus  oculi)  is  composed  of  a  large,  opaque 
segment  of  a  sphere,  forming  about  five-sixths  of  the  globe,  for- 
the  protection  of  its  contents,  and  a  smaller  transparent  seg- 
ment of  a  sphere,  implanted  upon  and  continuous  with  it  in 


Canal  of  Schlemm. 


8S~^*^^Canal  of 
«s»  Petit. 


SlIM'A    INTERNAL 
'  RECTUS 

MUSCLE. 


Canal  for 
central  artery. 


Optic  nerve. 


front.     The  optic  nerves  enter  the  eyeballs  to  their  nasal  side, 
in  the  direction  of  the  axes  of  the  orbit. 

It  is  composed  of  three  tunics  or  coats : — 

1.  Sclerotic  and  cornea, 

2.  Choroid,  iris  and  ciliary  processes, 

3.  Retina; 

And  three  humors,  -or  refracting  media : — 

1.  Aqueous  humor, 

2.  Crystalline  lens    (and  capsule), 

3.  Vitreous  humor,  or  body. 


ORGANS    OF    SPECIAL    SENSE.  331 

The  sclerotic  coat,  so  called  from  its  extreme  hardness, 
is  thicker  behind  (one  twenty-tilth  of  an  inch)  than  in  front 
(one-sixtieth  of  an  inch),  and  presents  two  surfaces  for  study — 
the  external  and  internal. 

The  external  swrface  is  smooth  and  white,  and  has  attached 
to  it  the  various  muscles  of  the  eye. 

The  internal  surface  is  grooved  for  the  passage  of  the 
ciliary  nerves,  and  connected  to  the  choroid  by  a  fine  areolar 
layer — the  lamina  fusca  (laminae  fascice  sclerce). 

Behind,  and  a  little  to  the  nasal  side,  where  the  optic  nerve 
enters,  it  presents  a  perforated  appearance — the  lamina  cribrosa 
—the  larger  opening  of  which — the  poms  opticus — transmits 
the  arteria  centralis  retinae;  the  others  transmit  the  ciliary  ves- 
sels and  nerves.  It  is  continuous  in  front  with  the  cornea,  over- 
lapping it  a  little  on  its  outer  margin. 

In  structure  it  is  made  up  of  white,  fibrous  tissue,  with  a 
small  quantity  of  elastic  fibers  and  connective-tissue  corpuscles. 

The  arteries  are  from  the  anterior  and  short  posterior 
ciliary. 

The  veins — venous  blood  removed  by  venas  vorticosse  and 
the  anterior  ciliary. 

The  nerves  are  from  the  ciliary. 

The  cornea  is  the  convex,  transparent,  nearly  circular 
tissue  forming  the  anterior  one-sixth  of  the  globe.  It  is  from 
niie  twenty-second  to  one  thirty-second  of  an  inch  in  thickness. 
Its  thickness  at  the  periphery  is  1.12  millimeters,  hence  its  pos- 
terior surface  is  more  curved  than  the  anterior.  Its  transverse 
diameter  is  a.  little  greater  than  the  vertical,  owing  to  the  over- 
lapping of  the  sclerotic  above  and  below.  It  is  composed  of 
four  layers : — 

1.  Conjunctival  epithelium,  or  anterior  layer  {epithelium  cornea;), 

2.  Cornea     proper,     or     sub-   f  Anterior    elastic    lamina     (lamina 

stantaa  propria,  \      elastica  anterior), 

3.  Posterior     elastic     lamina  "| 

I  lamina    elastica    paste-  j 

'  ""'  1 1  !  Cornea  proper; 

4.  Endothelial    lining    (endo-  (Membrane  of  Deseemet. 

thelium     camercB     ante-     | 
i  ioris) , 

The  conjunctival  epithelium  consists  of  several  layers  of 
cells  (columnar,  polyhedral  and  squamous)  covering  the  ante- 
rior surface  of  the  cornea,  continuous  wiih  the  conjunctiva. 

The  anterior  clastic  lamina  is  the  name  given  to  the  outer 
epithelial  layer  of  the  cornea  proper. 


362  HUMAN   ANATOMY. 

The  cornea  proper  is  made  up  of  a  transparent  fibrous 
structure,  identical  with  the  sclerotic,  and  consisting  of  about 
sixty  layers  or  lamina,  connected  by  a  cement  substance  inclos- 
ing corneal  spaces,  each  of  which  contains  a  corneal  corpuscle. 

The  posterior  elastic  lamina  consists  of  an  elastic  homo- 
geneous membrane,  internal  to  the  proper  structure  of  the 
cornea,  and  constituting,  with  the  epithelial  lining,  the  mem- 
brane of  Descemet,  or  Demours. 

The  structure  of  the  cornea  is  non-vascular,  being  nour- 
ished by  channels  representing  lymphatic  vessels,  and  continu- 
ous with  the  corneal  spaces.  The  nerves  derived  from  the 
ciliary  nerves  are  numerous,  and  form  between  the  outer  surface 
of  the  cornea  proper  and  the  epithelial  covering  the  subepithelial 
plexus,  from  which  is  given  off*  the  intraepithelial  plexus. 

The  second  tunic  consists  of  the  choroid,  lining  the  sclerotic 
coat  throughout;  the  iris,  the  circular  curtain  suspended  in  the 
aqueous  humor  and  perforated  by  the  pupil;  and  the  ciliary 
ligament  and  muscle  at  the  junction  of  the  two. 

The  choroid  (choroidea)  is  a  dark,  reddish-brown,  highly 
vascular  membrane,  lining  the  sclerotic  coat  from  the  optic 
nerve  to  the  ciliary  ligament,  where  it  projects  backward  in  a 
number  of  processes,  the  ciliary  processes.  It  is  in  contact 
externally  with  the  sclerotic,  to  which  it  is  attached  by  the 
membrana  fusca,  and  internally  with  the  retina. 

The  structure  consists  chiefly  of  a  dense  capillary  network. 

The  choroid  proper  consists  of  an  external  and  an  internal 
layer,  and  is  separated  from  the  sclerotic  by  the  lamina  supra- 
choroidea,  continuous  with  the  lamina  fusca  of  the   sclerotic, . 
and  from  the  pigmentary  layer  of  the   retina  by  the  lamina 
vitrea. 

The  external  layer  or  the  lamina  vasculosa  consists  of  a 
capillary  network,  derived  from  the  larger  branches  of  the  short 
ciliary  arteries,  inclosing  between  the  meshes  large,  star-shaped 
pigment  cells,  which  are  connected  together  by  a  delicate  stroma. 
They,  terminate  in  the  venw  vorticosce,  which  emerge  through 
the  sclerotic  midway  between  the  optic  nerve  and  the  margin  of 
the  cornea. 

The  internal  layer  is  also  composed  of  a  fine  capillary  net- 
work, derived  from  the  short  ciliary  arteries>  and  continuous  in 
front  with  the  vessels  of  the  ciliary  processes.  It  is  called  the 
tunica  Ruyschiana   (lamina  choriocapillaris) . 

The  lamina  basalis,  or  membrane  of  Bruch,  is  a  thin,  struc- 
tureless layer,  separating  the  pigmentary  layer  of  the  retina 
from  the  stroma  of  the  choroid. 


ORGANS    OF    SPECIAL    SENSE. 


363 


The  arteries  are  from  posterior  ciliary,  short  ciliary  (prin- 
cipally in  the  external  layer),  and  recurrent  branches  of  long 
and  anterior  ciliary. 

The  veins  converge  from  the  vena?  vorticosae  to  form  four 
or  five  trunks,  which  pierce  the  sclerotic  midway  between  the 
optic  nerve  and  corneal  margin  to  join  the  cavernous  sinus. 

The  nerves  are  the  long  and  short  ciliary. 


Fig.  ISO. 

Vessels  of  the  eye.  A,  conjunctival  vessels;  B,  anterior  ciliary 
vessels;  0,  vena  vorticosa;  D,  posterior  ciliary  arteries;  E,  central 
retinal   vessels.     (Hall.) 

The  ciliary  processes  (processus  ciliares)  are  a  series  of 
sixty  to  eighty  pigmented  vascular  processes  arranged  circularly 
around  the  lens  behind  the  iris,  and  composed  of  the  two  inter- 
nal layers  of  the  choroid  folded  inward.  They  are  continuous 
in  front  with  the  ins,  and  are  connected  behind  with  the  sus- 
pensory ligament  of  the  lens. 

The  structure  is  similar  to  that  of  the  choroid. 

Tin:  [BIS  is  a  thin,  circular  curtain,  suspended  in  the 
aqueous  humor,  between  the  lens  and  cornea,  and  perforated  by 
a  circular  aperture — the  pupil   (pupUla). 


364  HUMAN    ANATOMY. 

Its  circumference  is  connected  with  the  choroid,  and  also 
by  means  of  the  ciliary  ligament  with  the  sclerotic  and  cornea. 
The  sclerotic  contains  in  this  position,  near  its  junction  with 
the  cornea,  a  circular  canal  (lymph  canal,  or  venous  sinus),  the 
sinus  circularis  iridis,  or  canal  of  Schlemm  (sinus  venosus 
sclera?) . 

The  circumference  of  the  iris  is  also  connected  in  front 
with  the  cornea  by  pectinate  ligament  (ligamentum  pectinatum 
iridis),  derived  from  the  membrane  of  Descent et. 

The  structure  is  composed  of  four  elements : — 

.  1.  A  basement  membrane  and  polyhedral  cells,  continuous  with  the 
membrane  of  Descemet; 

2.  Stroma  (stroma  iridis)  consisting  of  bundles  of  fibrous  tissue 
and  cells; 

f  Circular     fibers      (m.     sphincter     pupilkc) , 
,r         ,       „,  ;       forming  the  sphincter  of  the  pupil; 

6.  Muscular  fibers,     ^  Radiating     fibers      (m.     dilator     pupillw) , 
[       forming  the  dilator  of  the  pupil; 

4.  Pigment,  consisting  of  polyhedral  or  round  pigment  cells,  dis- 
tributed for  the  most  part  to  the  posterior  surface,  which,  from  its 
deep-purple  tint,  has  been  called  the  uvea. 

The  arteries  are  from  the  long  and  anterior  ciliary  and 
from  the  ciliary  processes   (from  the  short  ciliary). 

The  veins  join  those  of  the  ciliary  processes  and  anterior 
ciliary  veins. 

The  nerves  are  the  long  ciliary  from  the  nasal  branch  of 
the  ophthalmic  (first  division  of  fifth),  and  ciliary  branches 
from  the  lenticular  or  ophthalmic  ganglion. 

The  circular  fibers  are  supplied  by  the  fibers  from  the 
third  or  motor  oculi,  the  radiating  fibers  are  supplied  by  the 
sympathetic. 

The  membrana  pupiUaris  is  a  delicate,  vascular  membrane, 
closing  the  pupil  in  the  fetus,  continuous  at  its  margin  with 
the  iris.  It  usually  disappears  about  the  eighth  month,  but 
occasionally  persists. 

The  ciliary  muscle  (m.  ciliaris)  is  a  grayish,  circular  band 
of  unstriated  fibers,  attached  to  the  fore  part  of  the  choroid. 
It  consists  of  two  sets  of  fibers — the  external  radiating  fibers 
(fibrce  meridianales  [Bruckei]),  dilator  pupillce — arising  from 
the  junction  of  the  sclerotica  and  cornea,  and  is  inserted  into 
the  choroid  opposite  the  ciliary  processes;  the  internal  circular 


ORGANS  OF  SPECIAL  SENSE. 


365 


Fig.  131. 

The  structure  of  the  human  retina.  I,  pigment  epithelium  layer; 
II,  rods  and  cones;  III,  granules  of  the  visual  cells;  IV,  outer  plexi- 
form  layer;  V,  layer  of  horizontal  cells;  VI,  layer  of  bipolar  cells; 
vil,  layer  of  amacrine  cells;  VIII,  inner  plexiform  layer;  IX,  gan- 
glion cell  layer;  X,  lay«r  ol'  nerve  fibers;  1,  diffuse  amncrin.'  cell; 
2,  diffuse  ganglion  cell;  3,  centrifugal  nerve  fiber;  l,  amacrine  asso- 
<i;ihon   fibers;  .J,   neuroglia  cells;  6,   Mullcr's  radial  fibers.     (Ball  after 

Cfreeff.) 


366 


HUMAN    ANATOMY. 


fibers  {fibrm  circular -es  [Mulleri]),  sphincter  pupillce,  pursue  a 
circular  course  around  the  insertion  of  the  iris.1 

It  is  the  muscle  of  accommodation,  its  contraction  draw- 
ing on  the  ciliar}?  processes,  relaxing  the  circular  fibers  described 
as  the  ligament  of  the  lens,  and  allowing  the  anterior  surface 
of  the  lens  to  become  more  convex  by  its  inherent  elasticity. 

The  retina  is  a  delicate,  white,  nervous  membrane,  the 


Fig.  132. 

Diagram  of  the  retinal  vessels.  1,  superior  temporal  artery;  2, 
superior  temporal  vein ;  3,  superior  nasal  vein ;  4,  superior  nasal  ar- 
tery; 5,  inferior  nasal  vein;  6,  inferior  nasal  artery;  7,  inferior  tem- 
poral vein;  8,  inferior  temporal  artery;  9,  macula  lutea;  10,  macular 
veins.     (Ball.) 


expansion  of  the  optic  nerve.  It  lines  the  eyeball,  being  in 
contact  externally  with  the  choroid  and  internally  with  the 
vitreous  body.     It  terminates  in  front  near  the  ciliary  body  in 

l  Quite  recently  it  has  been  the  consensus  of  opinion  among 
anatomists  that  the  circular  fibers  are  but  partially  attached  to  the 
radiating  fibers,  pursuing  a  circular  course  around  the  attachment  of 
the  iris.  These  circular  fibers  are  sometimes  designated  the  "ring 
muscle"  of  Miiller,  and  were  formerly  described  and  regarded  as  the 
"ciliary  ligament." 


ORGANS  OF  SPECIAL  SENSE.  ;;<;, 

an  irregular  margin,  the  ova  serrata,  but  is  prolonged  forward 
as  the  pars  ciliaris  to  the  iris.  Its  internal  posterior  surface 
presents  at  a  point  corresponding  to  the  axis  of  the  eyeball  a 
small,  round,  elevated  spot  of  yellowish  color  {macula  lutea), 
or  yellow  spot  of  Summering,  in  the  center  of  which  is  the 
fovea  centralis,  a  central  depression,  the  region  of  most  acute 
vision,  and  about  one-tenth  of  an  inch  to  its  nasal  side,  at  a 
point  corresponding  to  the  axis  of  the  orbit,  the  entrance  of 
the  optic  nerve,  an  oval,  bluish-white  depression,  with  distinct, 
often  pigmented  margins,  a  region  destitute  of  vision  and  called 
the  optic  disk  (porus  opticus).  Its  center  presents  the  arteria 
centralis  retina1,  giving  branches  to  the  upper  and  lower  nasal 
side  of  the  macular  region; 

The  structure  of  the  retina  is  exceedingly  complex,  con- 
sisting microscopically  of  ten  distinct  layers  from  within  out- 
ward, as  follows: — 

1.  Membrana  Urmtans  interna,  the  most  internal  layer  of  the 
retina,  forms  tin-  base  of  the  connective-tissue  framework'  of  the  retina, 
from  which  it  is  derived. 

2.  Tlie  fibrous  layer  consists'of  nerve  fihers,  the  termination  of  the 
optic  nerve  liber-. 

3.  The  vesicular  layer,  composed  of  a  layer  of  large,  flask-shaped 
ganglionic  cells.     It  is  wanting  in  the  macular  region. 

4.  Tin-  iiim  >•  molecular  lay<  r  i-  composed  of  a-  layer  of  glandular- 
like  structure,  forming  a  reticulum  inclosing  minute  granules. 

5.  The  vn/ner  nuclear  layer  is  composed  of  three  sets  of  nuclear 
bodies,  the  first  resembling  bipolar  nerve  cells,  the  second  without 
branches,  and  third  continuous  with  the  radiating  fibers,  or  fibers  of 
VI  filler. 

G.  The  ouicr  molecular  layer  resembles  closely  the  inner  molecular 
layer,  from  which  it  differs  only  by  containing  branched  stellate  cells. 

7.  The  outer  nuclear  Un/er  is  composed  of  several  layers  of  nuclear 
cells,  separable  into  two  kinds,  the  rod  granules  and  cone  granules,  both 
continuous  with  the  rods  and  cones  of  Jacob's  membrane. 

s.  The  membrana  Umitans  externa  is,  like  the  internal  limiting 
membrane,  derived  from  the  radiating  fibers,  or  fibers  of  Mailer. 

'.i.  Jacob's  membrane,  or  the  layer  of  rods  and  cones,  consists  of 
two  distinct  kinds  of  cells — the  rods  and  cones,  distributed  alternately 
throughout   this   layer,  the   rods  being  much  more  numerous. 

the  rod-  are  solid,  stand  perpendicularly  to  the  surface,  and  con- 
-i-t   of  two  portions — an  outer  striated  and  an   inner  granular. 

The  cone-  are  flask-shaped,  with  their  pointed  extremities  toward 
the  choroid.  Thej  a  No  consist  of  two  portion- — an  outer  striated  and 
an  inner  granular. 

ID.  The  pigmentary  layer  was  formerly  described  as  a  layer  of  the 
choroid.  It  has  received  the  name  of  tapetum  nigrum,  ('insisting  of  a 
layer  of  pigmented  hexagonal  epithelial  cells. 

In  main  of  tin'  lower  animal-,  this  layer  on  the  posterior  surface 
i-   destitute   <<i   pigment*   and    is  called   from   its   iridescent    lustre  the 

!<![,</ Km    hitidjnii. 


368  HUMAN   ANATOMY. 

The  radiating  fibers,  or  fibers  of  Midler,  consist  of  connective- 
tissue  fibers,  connecting  all  the  layers  together,  and  forming  the  mem- 
brana  li  mi  tans  interna  and  the  membrana  limitans  externa. 

The  structure  of  the  retina  at  the  macula  lutea  differs  in 
the  following  manner :  the  cones  only,  of  Jacob's  membrane  are 
present;  the  Tesicnlar  layer  consists  of  several  strata,  and  in 
the  outer  nuclear  layer  only  the  cone  fibers  are  present. 

At  the  fovea  centralis  only  the  cones  of  Jacob's  membrane, 
the  outer  nuclear  layer,  and  the  internal  granular  layer  are 
present. 

The  arteria  centralis  retina?  supplies  only  as  far  as  the 
inner  nuclear  layer. 

THE    HUMORS     OF    THE    EYE. 

The  aqueous  humor  {humor  aqueus)  is  a  transparent, 
alkaline,  serous  fluid,  small  in  quantity,  weighing  four  to  five 
grains,  and  filling  the  anterior  and  posterior  chambers  of  the 
eye.  It  is  composed  of  water,  96.7;  extractive  matters,  prin- 
cipally chloride  of  sodium  and  albumin,  0.1. 

The  anterior  chamber  (camera  oculi  anterior)  is  the  space 
(about  2.7  millimeters  in  depth)  between  the  iris  and  the 
cornea. 

The  posterior  chamber  (camera  oculi  posterior)  is  the 
space  between  the  anterior  surface  of  the  lens  and  the  iris.  It 
amounts  to  a  space  only  at  the  circumference,  the  two  being  in 
contact  at  the  posterior  surface. 

The  crystalline  lens  (lens  crystallina)  is  a  biconvex, 
transparent,  elastic  body,  suspended  with  its  capsule  (capsula 
lentis),  surrounded  by  the  ciliary  processes.  It  is  more  convex 
on  its  posterior  surface  (anterior  surface  has  an  average  radius 
of  10  millimeters,  the  posterior  6  millimeters),  and  is  received 
into  a  hollow  depression  in  the  hyaloid  membrane. 

It  measures  about  one-third  inch  in  diameter,  one-fourth 
inch  in  axis,  and  weighs  from  four  to  four  and  one-half  grains. 

Its  index  of  refraction  increases  from  the  periphery  to  the 
center,  with  an  average  of  1.4371. 

Its  composition  consists  of  about  60  per  cent,  water;  solu- 
ble albuminous  matter,  35  per  cent.;  insoluble  albuminous  mat- 
ter, 2.5  per  cent. ;  cholesterin  and  fat,  2  per  cent. 

The  structure  of  the  lens  consists  of  concentric  laminge, 
made  up  of  hexagonal  prisms,  about  one-'five-thousandth  inch 
in  breadth,  united  laterally  by  dentated  margins,  and  curving 


ORGANS  OF  SPECIAL  SENSE.  .;,;;, 

round  the  borders  of  the  lens.     The  lamina'  are  arranged  into 
three  triangular  segments. 

The  centra]  portion,  or  nucleus,  is  unstratified,  while  the 
miter  layers,  or  cortex,  each  contain  a  nucleus,  forming  a 
nuclear  layer. 

The  capsule  of  the  lens  (capsula  lentis)  is  a  clear,  elastic, 
brittle  memhrane,  inclosing  the  lens,  and  held  in  position  hv 
the  suspensory  ligament.  Its  anterior  layer  is  thicker,  and  is 
attached  to  the  lens  by  a  layer  of  polygonal  nucleated  cells, 
which  break  down  post-mortem  to  form  the  liquor  Morgagni. 

The  canal  of  Petit  (spatia  zonularia)  is  ahout  one-tenth 
inch  in  diameter,  encircling  the  capsule  of  lens.  Its  hase  is 
formed  by  the  capsule,  and  it  is  hounded  in  front  by  suspensory 
ligament,  behind  by  the  hyaloid  membrane  of  the  vitreous 
humor. 

The  suspensory  ligament,  or  zonula  of  Zinn  (zonula  cili- 
aris),  is  a  thin,  transparent  structure,  extending  from  the  mar- 
gins of  the  hyaloid  fossa,  where  it  is  continuous  with  hyaloid 
membrane,  to  the  anterior  margin  of  the  lens. 

Tin:  vitreous  humor,  or  body  (cor/nis  vitreum),  is  a 
clear,  albuminous  fluid,  filling  the  cavity  of  the  retina,  hollowed 
out  in  front — hyaloid  fossa  (fossa  hyaloidea) — for  the  lens, 
and  inclosed  in  the  hyaloid  membrane  (membrana  hyaloidea). 
It  is  composed!  of  water,  with  a   few  salts  and  a  little  albumin. 

Its  structure  is  finely  reticular,  particularly  in  the  fetus. 

Thi'  canal  of  Stilling,  canal  of  Cloquet,  or  hyaloid  canal 
(canalis  hyaloideus) ,  is  a  canal  extending  in  the  fetus  from  the 
entrance  of  the  optic  nerve  to  the  lens,  containing  fluid,  and 
lined  by  a  fold  of  hyaloid  membrane. 

In  the  Ictus  a  canal  extends  parallel  hut  independent  of 
tlii--  and  transmits  a  minute  artery  to  the  capsule  of  the  lens. 

The  hyaloid  membrane  (membrana  hyaloidea)  is  a  delicate 
capsular  memhrane,  investing  the  vitreous  body,  excepting  its 
anterior  surface,  sends  fibrous  septa  into  the  structure  of  the 
Vitreous,  and  IS  continuous  in  front  with  the  posterior  capsule, 
and  with  the  anterior  capsule  through  the  suspensory  ligament. 

\l  I  8<  l.i:s    OF    Till':    EYEBALL. 

Recti  -  Si  periob  (m.  rectus  superior) .— Origin,  sheath,  of 

the  optic  nerve  and   upper  margin  of  optic  foramen;  insertion, 
into    upper   surface   of    sclerotic   coat,    three   or    four    lines    from 

corneal  margin;  action,  rotates  the  eyeball  upward:  nerve],  third 

cranial. 

24 


370 


HUMAN    ANATOMY. 


Eectus  Inferior  (m.  rectus  inferior). — Origin,  from 
lower  and  inferior  part  of  optic  foramen  (ligament  of  Zinn — 
annulus  tendineus  communis)  ;  insertion,  into  lower  surface  of 
sclerotic;  action,  rotates  the  eyeball  downward;  nerve,  third 
cranial. 

Rectus  Interntjs  (m.  rectus  internus). — Origin,  same  as 


£? 


Rl- 


The  orbital  muscles.  Lp,  levator  palpebrse  superioris;  Os,  supe- 
rior oblique;  lis,  superior  rectus;  Rl,  external  rectus;  Oi,  inferior 
oblique;  Ri,  inferior  rectus;  Rm,  internal  rectus;  Tr,  trochlea.     (Ball.) 


inferior  rectus;  insertion, -into  inner  surface  of  sclerotic;  action, 
rotates  the  eyeball  inward ;  nerve,  third  cranial. 

Eectus  Exteenus  (m.-  rectus  lateralis). — Origin,  by  two 
heads* — lower,  from  ligament  of  Zinn  and  lower  margin  of 
sphenoidal  fissure ;  upper,  from  outer  margin  of  optic  foramen ; 
insertion,  into  outer  surface  of  sclerotic;  nerve,  abducens,  or 
sixth  cranial.  Passing  between  the  two  heads  are  the  ophthal- 
mic vein,  the  third,  nasal  branch  of  fifth  and  sixth  nerves. 


ORCAXS  OF  SPECIAL  SENSE. 


371 


Superior  Oblique  (m.  obliqims  superior). — Origin,  from 
iuuer  margin  of  optic  foramen.  Its  tendon  passes  through  a 
pulley  {trochlea  in.  obliqm  superior)  near  the  internal  angular 
process  of  the  frontal  bone;  insertion,  into  sclerotic  between 
external  and  superior  recti,  midway  between  entrance  of  optic 
nerve  and  the  cornea;  action,  rotates  the  eyeball  on  its  axis; 
nerve,  fourth,  or  patheticus. 

Inferior  Oblique  (in.  obliquus  inferior). — Origin,  orbital 
plate    of    superior    maxilla;    insertion,    near    that    of    superior 


Supra-orbital 


Lacrimal 


Muscular  and  ciliary 


Anterior  meningeal 
Ophthalmic 


Superior  rectus 
Levator  palpebral  saperioris 


Anterior  ethmoidal 
Muscular  trunk 

Ciliary 

Arteri:\  centralis 
Posterior  ethmoidal 


Optio  nerve 
Internal  carotid 


Fig.  134. 
Ophthalmic  artery  and  branches.     (Hall,   after  Merkel  and  Kallius.) 


oblique,  between  external  and  superior  recti;  action,  rotates  the 
eyeball  on  its  axis;  nerve,  third  cranial. 

The  arteries  oi  the  globe  of  the  eye  are: — 

1.  The  short  ciliary,  enter  through  the  sclerotic  around  the 
optic  nerve,  to  supply  the  choroid  and  ciliary  processes. 

2.  The  long  ciliary  arteries,  two  in  number,  pierce  the 
Bclerotie,  ran  forward  between  the  choroid  and  sclerotic  to  the 
ciliary    muscle,    which    they    Supply,    and    where    they    form    an 

anastomotic  circle  about  the  iris. 

:;.  The  anterior  ciliary  art  cries,  five  or  six  in  number,  enter 
the  sclerotic  in  front,  supply  the  ciliary  process,  and  anastomose 
about  the  irb. 


372  HUMAN    ANATOMY. 

4.  The  arteria  centralis  retina'  supplies  the  retina,  dividing 
into  four  or  five  branches,  which  enter  as  deeply  as  the  inner 
nuclear  layer. 

The  other  arteries  supplying  the  eye  and  its  appendages 
are  derived  from  the  ophthalmic  branch  of  the  internal  carotid 
(the  same  source  as  the  ciliary  arteries),  the  anterior  cerebral 
branch  of  the  internal  carotid,  and  the  infraorbital  branch  of 
the  internal  maxillary. 

The  branches  of  the  ophthalmic  are : — 

Lachrymal ; 

Supraorbital; 

Anterior  and  posterior  ethmoidal; 

Palpebral; 

Frontal ; 

Nasal.      (For  description  see  Arterial  System.) 

The  veins  of  the  eyeball  emerge  as  the  vence  vorticosce,  unite 
with  the  other  veins  to  form  two  main  trunks — the  ophthalmic 
and  inferior  ophthalmic  veins — to  terminate  in  the  cavernous 
sinus.  The  ophthalmic  vein  anastomoses  freely  with  the  angu- 
lar vein,  the  commencement  of  the  facial  at  the  inner  angle  of 
the  orbit. 

The  nerve  of  special  sense,  the  optic  or  second  cranial,  sup- 
plies the  eye  and  its  appendages;  motor  nerves,  the  third  and 
fourth ;  branches  of  the  fifth  and  sixth,  and  filaments  from  the 
sympathetic. 

Sensory  nerve,  ophthalmic  division. of  the  trifacial,  or  fifth 
cranial  {vide  Cranial  Nerves). 

Sympathetic  branches,  derived  chiefly  from  the  ciliary  gan- 
glion, Meckel's  ganglion,  and  the  cavernous  and  carotid  plexuses 
(vide  Cranial  Sympathetic  Ganglion). 

APPENDAGES    OP    THE    EYE. 

The  appendages  of  the  eye  (tutamina  oculi)  include:  The 
eyebrows  (supercilia) ,  the  eyelids  (palpebrce),  conjunctiva,  and 
the  lachrymal  apparatus  (apparatus  lacrimalis)  ;  lachrymal 
gland,  lachrymal  sac,  nasal  duct. 

The  eyebrows  (supercilia)  are  the  elevated  arches  of  skin 
surmounting  the  upper  margins  of  the  orbits,  covered  with 
short,  thick  hairs. 

The  eyelids  (palpebrce)  are  two  movable  folds,  covering 
and  protecting  the  front  of  the  eye.  The  upper  lid  (palpebra 
superior)  is  larger,  longer;  and  more  movable,  being  supplied 
with  a  special  muscle — the  levator  palpebra?  superioris. 


ORGANS  OF  SPECIAL  SENSE.  373 

The  lids  are  separated  by  an  elliptical  fissure — the  fisswra 
palpebrarum — and  connected  at  their  angles  of  junction  by  the 
outer  (angulus  oculi  lateralis)  and  inner  (angulus  oculi  me- 
dialis)  canthi. 

On  the  nasal  side  the  lids  are  separated  by  a  triangular 
space — the  lacas  lacrvmalis — at  the  outer  angles  of  which  are 
the  lachrymal  papilla',  surmounted  by  the  panel  am  lacrimale, 
the  commencements  of  the  lachrymal  canal.  The  lacas  lacri- 
malis  is  filled  by  the  caruncula  lacrimdlis,  a  mass  of  follicles 
resembling  the  "Meibomian  glands,  and  covered  by  the  con- 
junctiva. 

The  structure  of  the  eyelids,  from  without  inward,  is  as 
follows: — 

Skin,  subcutaneous  areolar  tissue,  fibers  of  the  orbicularis  muscle, 
tarsal  cartilage,  fibrous  membrane,  Meibomian  glands,  vessels  and 
nerves ; 

The  skin  is  thin,  and  attached  by  a  very  loose  areolar  tissue  to  the 
muscle  beneath; 

The  fibers  of  the  orbicularis  are  pale,  thin,  and  act  involuntarily; 

The  tarsal  cartilages  are  two  plates  of  firm  connective  tissue;  the 
superior  (tarsus  superior),  the  larger,  is  semilunar  in  shape,  the  in- 
ferior (tarsus  inferior)  is  elliptical.  The  inner  margins  are  fixed  to  the 
orbit  by  tendo  oculi; 

The  fibrous  membrane  of  the  litis,  or  tarsal  Uga/ment,  passes  over 
the  anterior  surface  of  the  tarsal  cartilage,  being  attached  to  its  free 
margin  below  and  to  the  margin  of  the  orbit  externally: 

The  Meibomian  glands  (glandules  tarsales  [Meibomi]  ),  about  thirty 
in  number  in  the  upper,  a  U>\v  less  in  the  lower  lid.  are  arranged  ver- 
tically on  the  inner  surface  of  the  cartilages;  they  are  straight,  seba- 
ceous follicles,  into  which  open  a  number  of  secondary  follicles,  termi- 
nating above  in  a  blunt  extremity,  and  opening  below  on  the  free  margin 
of  the  lids  by  small  foramina,  corresponding  to  the  number  of  tubules; 

The  eyelashes  (cilia),  are  arranged  on  the  free  border  of  the  lids 
ill  two  or  three  rows. 

The  CONJUNCTIVA  is  the  mucous  lining  membrane  of  the 
front  of  the  eye.  It  consists  of  two  portions — the  bulbar. 
reflected  over  the  sclerotic  and  cornea,  and  the  palpebral  por- 
tion; lining  the  internal  surface  of  the  lids. 

The  bulbar  portion  {tunica  conjunctiva  bulbi)  is  loosely 
connected  with  the  sclerotic,  hut  over  the  cornea  if  becomes 
very  thin,  consisting  only  of  the  epithelial  layer. 

The  palpebral  portion  (I  unit  a  conjunctiva  palpebrarum)  is 
thick,  highly  vascular,  and  contains  many  papilla'.  At  the 
inner  angle  of  the  eye  it  forme  a  semilunar  fold,  the  plica  semi- 
lnnari-  [plica  semilunaris  conjunctiva?) -  the  rudiment  of  the 
nictitating  membrane  of  birds,  the  membrana  niclilans. 


74 


HUMAN    ANATOMY. 


The  point  of  reflection  is  called  the  fornix  conjunctivae, 
and  the  reflected  portions  the  superior  and  inferior  palpebral 
folds. 

The  lachrymal  apparatus  (apparatus  lacrimalis)  consists  of 
the  lachrymal  gland,  canals-,  sac  and  nasal  duct. 

The  lachrymal  gland  (glandula  lacrimalis)  is  an  oval, 
glandular  body,  about  the  shape  and  size  of  an  almond,  sit- 
uated in  a  depression  in  the  upper  surface  of  the  orbit  near 
the  external  angular  process. 

The  anterior  portion  of  the  gland  is  sometimes  described 


ducts'  of/ 
lachrymal, 

GLAND 


CARUNCLE 
I  CANALICULUS 

LACHRYMAL  SAC 


NASAL   DUCT 


Fig.  135. 
The  lachrymal  apparatus.     (Gerrish,   after  Testut;  EcMey.) 

as  a  separate  lobe — the  palpebral  portion  of  the  gland,  or 
accessory  gland  of  Eosenmiiller  (glandula  lacrimalis  inferior)  ; 
the  back  part  of  the  gland  is  designated  the  superior  lachrymal 
gland  (glandula  lacrimalis  superior). 

The  gland  is  attached  to  the  bony  roof  of  the  orbit  by  the 
tarso-orbital  fascia. 

The  ducts,  seven  to  ten  in  number,  open  upon  the  con- 
junctiva near  its  point  of  reflection  by  minute  orifices  arranged 
in  a  row. 

The  laclirymal  canals  commence  at  the  puncta  lacrimalia, 
at  the  summits  of  the  lachrymal  papilla  (carunculus  lacrimalis), 
and  descend  by  two  canaliculi  to  empty  into  the  lachrymal  sac. 

The  superior  canal  (ductus  lacrimalis  superior)  descends 
obliquely   inward   and   downward,   while   the    inferior    (ductus 


ORGANS  OF  SPECIAL  SENSE.  375 

lacrimalis   inferior)    descends  at  first   and    then   passes  nearh 
horizontally  inward. 

The  lachrymal  sac  (saccus  lacrimalis)  is  the  oval, 
dilated,  upper  portion  of  the  nasal  duet,  lodged  in  a  deep  groove 
formed  by  the  nasal  process  of  the  superior  maxilla  and  the 
lachrymal  bone.  It  is  crossed  by  the  tensor  tarsi  muscle,  which 
acts  as  a  compressor,  and  receives  a  fibrous  expansion  from  the 
tendo  oculi. 

Its  structure  is  made  up  of  a  fibrous  elastic  coat,  lined  bv 
mucous  membrane  continuous  with  the  nose  and  conjunctiva. 

The  nasal  duct  {ductus  nasolacrimalis)  is  a  membranous 
tube  about  three-quarters  of  an  inch  in  length,  extending  from 
the  lachrymal  sac  to  the  inferior  meatus  of  the  nose,  and  lining 
the  bony  lachrymonasal  canal.  It  passes  backward,  downward, 
and  outward,  and  is  protected  at  its  inferior  extremity  bv  a 
valve  of  mucous  membrane — the  valve  of  Hasner  (plica  lacri- 
malis \  Hasneri]). 

The  mucous  lining  is  continuous  with  that  of  the  sac,  hut 
instead  of  having  squamous  epithelium  it  is  ciliated  in  the  duct, 

THE     EAR. 

The  ear  (organon  a  ud it  us) — the  organ  of  hearing — is 
contained  in  the  petrous  and  mastoid  portions  of  the  temporal 
hone,  and  consists  of  three  divisions, — external  ear,  middle  ear 
or  tympanum  and  internal  ear  or  labyrinth: — 


or  meatus; 


1.  External  ear,  (    Auricle  or  pinna. 

I.    External  auditory  canal 

f   Membrana  tympani, 

2.  Middle   ear   o'r    tympanum,   J     Tyn.pai.ic  cavity. 

'  ',      .Mastoid    sinuses. 

(_    Eustachian  tube; 

{Vestibule, 
Semicircular    canals, 
Cochlea ; 
■>.   internal     ear    or  j 

labyrinth.  \  r  TT,   .  , 

[     Utricle, 

I   Membranous    portion.     \    Saccule, 

1    semicircular    canals. 
I   Cochlea. 

The   external    ear    includes   two    parts,    the    auricle   and    the 
external  auditory  canal. 


376  HUMAN    ANATOMY. 

AURICLE     (AURICULA),    OR    PINNA. 

The  external  prominent  portion  is  composed  of  cartilagin- 
ous segments,  connected  together  by  ligaments  and  muscles 
richly  supplied  with  blood  vessels,  nerves,  and  lymphatics,  and 
covered  with  skin.  It  presents  the  following  elevations  and 
depressions : — 

Fossa  of  the  helix,  a  depression  between  the  helix  and  anti- 
helix  ; 

Fossa  of  the  antibelix  (fossa  triangularis  [auricula]),  a 
depression  above  the  bifurcation  of  the  antihelix; 

Tragus,  the  prominence  in  front  of  the  concha,  usually  cov- 
ered with  hair; 

Antitragus,  a  small,  conical  eminence  behind  the  tragus, 
from  which  it  is  separated  by  the  incisura  intertragica ; 

Lobule  (lobulus  auricula),  the  soft,  rounded  portion  de- 
pending below  the  antitragus; 

Concha,  a  deep  cavity,  surrounded  by  the  helix,  leading  into 
the  external  meatus. 

Muscles. — The  muscles  of  the  auricle  include  two  sets,  the 
extrinsic  muscles,  already  described  (vide  Muscles),  of  which 
there  are  three — the  attolens  aurem,  attrahens  aurem  and  re- 
trahens  aurem — and  the  intrinsic  muscles,  but  slightly  devel- 
oped, of  which  there  are  two  sets,  four  on  the  anterior  surface 
of  the  auricle-^-the  tragicus  (m.  tragicus),  antitragicus  (m. 
antitragicus) ,  helicis  major  (m.  heHcis  major),  and  helicis 
minor  (m.  helicis  minor) — and  two  on  the  posterior  surface, 
transversus  auriculae  (m.  transversus  auricula3)  and  obliquus 
auriculae  (m.  obliquus  auricula'). 

Arteries,  auricular  branch,  from  the  occipital;  posterior 
auricular,  from  the  external  carotid;  and  anterior  auricular, 
from  the  temporal.     The-  veins  correspond  to  the  arteries. 

Nerves,  auricular  branch,  from  the  pneumogastric ;  auric- 
ulotemporal branch,  from  the  inferior  maxillary;  occipitalis 
major  and  occipitalis  minor;  auricularis  magnus,  from  the 
cervical  plexus;  and  posterior  auricular,  from  the  facial. 

Auditory  caxal,  or  meatus  auditorius  externus  (meatus 
acusticus  externus),  is  an  osseocartilaginous  canal,  about  one 
and  one-fourth  inches  in  length,  extending  from  the  concha  to 
the  tympanic  membrane. 

The  osseous  portion  (pars  ossea  tuba  auditivce,  or  semi- 
canalis  tuba,  auditivce)  forms  about  two-thirds  of  the  passage, 
and  consists  in  greater  part  (anterior  and  lower)  of  a  curved 
plate  of  bone — the  annulus  tympanicus. 


ORGANS  OF  SPECIAL  SENSE. 


377 


The  anterior  and  upper  part  of  the  ring  presents  two  spines 
— spina  tympanica,  major  and  minor — for  the  Ligaments  of  the 
malleus. 

The  sulcus  tympanicus  is  a  furrow  on  the  inner  edge  of 
the  ring,  for  the  attachment  of  the  tympanic  membrane. 

The  cartilaginous  portion  (pars  cartUaginea  tuba'  audi- 
tiva  )  forms  about  one-third  of  the  passage,  and  consists  of  the 
inverted  cartilage  of  the  tragus  and  concha,  the  upper  and  back 
part  of  which  is  deficient,  the  cleft  being  filled  with  fibrous 
tissue. 


Fig.  136. 

rnal,  middle,  and  internal  ear.  1,  external  ear;  2,  middle  ear: 
•",,  internal  ear:  4.  pinna;  5.  helix;  0,  antihelix;  7  fossa  naviculars; 
s.  fossa  innominata;  9,  tragus;  10,  antitragus:  11,  concha;  12,  lobe; 
I .;.  meatus  auditorius  externus;  14,  tympanic  membrane;  15,  promon- 
tory: in,  foramen  rotundum;  17,  posterior  wall  of  the  tympanum;  is, 
OBSlcula  auditus;  19,  Eustachian  tube;  20,  narrow  canal;  21,  vestibule: 
22.  semicircular  canals,  the  superior,  posterior,  and  horizontal;  23, 
ampullae,  21.  cochlea;  26,  prominence  caused  by  the  scala  vestibuli; 
20,  scala  tympani.     (Boenning.) 


The  canal,  including  the  tympanic  membrane,  is  lined 
throughout  with  skin,  containing  short  hairs,  vascular  papilla', 
sebaceous  and  ceruminous  glands   (glandvXai  ceruminosw) . 

Arteries — branches  of  the  internal  maxillary,  posterior 
auricular  and  temporal  branches  of  external  carotid. 

Nerves  from  the  auriculotemporal  branch,  the  inferior 
maxillary  and  auricular  branch  of  the  pneumogastric. 


378  HUMAN   ANATOMY. 


MIDDLE    EAR   (aURIS    MEDIA),    OR    TYMPANUM, 

is  an  irregular  cavity  (cavum  tympani) ,  situated  between  the 
auditory  canal  and  the  labyrinth,  communicating  with  the 
pharynx  through  the  Eustachian  tube,  and  also  with  the  mas- 
toid cells.  It  contains  a  chain  of  movable  bones,  part  of  the 
chorda  tympani  nerve,  and  is  filled  with  air.  Its  average  diam- 
eters are  about  half  an  inch  in  height  and  width,  and  a  line  or 
two  in  depth  from  without  inward.  It  is  lined  with  mucous 
membrane,  continuous  with  that  of  the  Eustachian  tube  and 
mastoid  cells,  and  which  is  reflected  over  all  the  tympanic  con- 
tents. It  is  bounded  by  a  roof,  floor  and  four  walls,  which 
present  the  following  points : — ■ 

Eoof  (paries  tegmentalis) ,  a  very  thin  plate  of  bone  {teg- 
men  tympani),  separates  the  tympanum  from  the  cranial  cav- 
ity, and  corresponds  to  a  depression  on  the  anterior  wall  of  the 
petrous  bone; 

Floor  (paries  jngularis),  forms  the  bottom  of  the  jugular 
fossa,  and  presents: — 

The  opening  for  Jacobson's  nerve,  the  tympanic  branch  of  the 
glossopharyngeal    ( n.  tympanicus ) . 

Outer  wall,  formed  by  the  tympanic  membrane,  Shrapnell's 
membrane,  and  the  annulus  tympanicus  surrounding  it: — 

Notch  of  Rivinus  (incisure/,  tympanica  [Rivini]),  incomplete  upper 
ring  of  bone; 

Iter  chordae  posterius  (canaliculus  chordce  tympani),  gives  en- 
trance to  chorda  tympani  nerve; 

Iter  chorda*  anterius,  or  canal  of  Huguier,  gives  exit  to  same; 

Glaserian  fissure  (fissura  petrotympanica  [Glaseri]),  above  and  in 
front  of  annulus  tympanicus,  receives  the  anterior  ligament  of  the  mal- 
leus, the  long  process  of  the  malleus,  and  the  tympanic  artery; 

Pouches  of  the  membrama  tympani,  are  two  or  three  pockets 
formed  by  the  doubling  of  the  mucous  membrane  around  the  chorda 
tympani  nerve. 

Inner  wall  (paries  labyrinthica) ,  separates  the  tympanum 
from  the  labyrinth : — 

Fenestra  ovalis  (fenestra  vestibuli) ,  an  oval  window,  leading  to 
the  vestibule,  closed  by  the  membrane  to  which  the  base  of  the  stapes 
is  attached; 

Fenestra  rotunda  (fenestra  cochlea?),  .a  round  window,  leading  to 
the  scala  tympani,  but  closed  also  by  a  membrane — membrana  tympani 
secundaria. 

Promontory  (promontorium) ,  two  grooves,,  marking  the  first  turn 
of  the  cochlea,  and  separating  the  fenestras  ovalis  and  rotunda; 


ORGANS    OF    SPECIAL    SENSE.  379 

Rounded  eminence  of  the  aqueductus  Fallopii  (prominentia  canaiis 
facialis),  a  small  conical  eminence  above  the  fenestra  ovalis,  which  con- 
tains  within  it  the  aqueductus  Fallopii,  the  long-  canal  for  the  facial 
nerve. 

Posterior  wall  (paries  mastoidea)  : — ■ 

Openings  of  tfo  mastoid  cells,  three  or  four  in  number,  connect 
these  sinuses  with   the  tympanum. 

Anterior  wall  (paries  carotica),  is  a  thin  plate  of  bone, 
which  separates  the  tympanum  from  the  carotid  canal. 

Openings  of  the  canal  for  tensor  tympani  (semicanalis  m.  Icnsoris 
tympani),  lies  above  and  parallel  with  the  canal  for  the  Eustachian  tube, 
and  transmits  the  tensor  tympani  muscle; 

Opening  of  Eustachian  tube  (tuba  auditiva  [Eustachii ] ) ,  the 
larger  of  the  two,  is  separated  from  the  former  by  a  thin  plate  of  bone, 
the   processus  cochleariformis    (septum   canaiis   musculotubarii) . 

The  tympanum  is  divided  into  two  parts — the  attic  (re- 
cessus  epitympanicus)  of  the  tympanum  and  the  atrium.  The 
former  is  situated  on  a  plane  directly  above  the  atrium,  and  is 
bounded  above  by  the  tegmen,  externally  by  auditory  plate,  and 
internally  by  prominence  of  the  tympanum.  On  the  outer  part 
of  the  attic  is  a  smooth  surface  called  the  scute  (Leidy). 

The  Eustachian  tube  (tubce  auditiva  \ Eustachii])  is  an 
osseocartilaginous  canal,  one  and  one-half  to  two  inches  in 
length,  extending  from  the  tympanum  to  the  pharynx. 

It  is  about  one-third  osseous  and  two-thirds  cartilaginous, 
and  lined  with  ciliated  epithelium  continuous  with  the  pharynx 
and  tympanum.  Its  pharyngeal  orifice  is  trumpet-shaped,  and 
opens  at  the  side  of  the  pharynx,  behind  the  inferior  meatus. 

Muscles  of  the  Eustachian  tube: — 

Tensor  palati  (m.  tensor  veil  palatini),  the  most  important 
has  been  described  [vide  Palatal  Region).  Its  action  is  to  pull 
tin'  anterior  wall  of  the  tube  outward  and  downward,  and  widen 
the  canal. 

Internal  Pterygoid  {vide  Muscles). — Some  fibers  are  in- 
serted into  the  floor  of  the  tube.     It  net-  as  tensor  of  the  fascia. 

lAgamenta  salpingopharyngeal,  arises  from  the  superior 
and  middle  constrictors  nf  the  pharynx,  and  is  inserted  by  three 
to  five  tendinous  cords  into  the  pharyngeal  orifice  of  the  tube. 

Action,  opens    the   tube. 

Arteries  of  Eustachian  Tube. — Pharyngeal  from  the  exter- 
nal carotid,  middle  meningeal  from  the  internal  maxillari   ami 

-mall   branches  from   the  internal  carotid. 


380  HUMAN    ANATOMY. 

Nerves,  by  branches  from  the  glossopharyngeal,  inferior 
maxillary,  otic  ganglion  and  facial  nerve. 

Membrana  tympani  is  a  thin,  parchment-like  membrane, 
stretched  upon  the  annulus  tympanicus,  forming  the  bottom  of 
the  external  auditory  canal,  and  separating  it  from  the  tym- 
panum. It  is  placed  obliquely  downward  and  inward  at  an 
angle  of  45°. 

Structure. — Its  three  layers  are  :— 

External  or  cuticular,  derived  from  the  skin  of  the  meatus; 

Middle  or  fibrous,  consisting  of  two  sets  of  fibers,  radiating 
and  circular,  the  latter  forming  a  tendinous  ring  around  the 
margin ; 

Internal  or  mucous,  continuous  with  the  mucous  membrane 
of  the  tympanum. 

Its  outer  surface  presents : — 

Manubrium  of  malleus,  projecting  downward  and  back- 
ward ; 

Processus  gracilis  of  malleus,  projecting  outward  above  the 
manubrium ; 

Umbo  (umbo  membrance  iympance),  a  depression  of  the 
membrane  formed  by  the  lower  end  of  the  manubrium; 

Yellow  spot,  the  cartilaginous  end  of  the  manubrium; 
pyramid  of  light,  a  triangular  cone  of  reflected  light  in  the 
antero-inferior  quadrant  of  the  membrane. 

Inner  surface  (vide  Outer  Wall  of  Tympanum). 

Arteries,  tympanic  branch  of  inferior,  branch  from  the 
internal  carotid. 

Nerves,  from  the  superficial  temporal  branch  of  the  tri- 
facial and  from  the  tympanic  plexus. 

OSSICLES    OF    THE    TYMPANUM    (OSSICULA    AUDITUS). 

The  small  bones  of  the  tympanum  are  three  in  number, 
and  connect  the  membrana  tympani  with  the  membrane  closing 
the  fenestra  ovalis.    They  are  the 

1.  Malleus,  or  hammer,  consists  of  a  head  (capitulum 
mallei),  neck  (collum  mallei),  manubrium  or  handle,  processus 
gracilis  (processus  anterior  \Foli%\),  and  processus  brevis  (pro- 
cessus lateralis).  The  manubrium  (manubrium  mallei)  is  at- 
tached to  the  membrana  tympani,  and  has  the  tendon  of  the 
tensor  tympani  attached.  Processus  gracilis  is  lodged  in  the 
Glaserian  fissure. 

2.  Incus,  or  anvil,  consists  of  a  body  (corpus  incudis)  and 
a  long  (eras  longum)   and  short  processes  (crus  breve).    The 


ORGANS    OF    SPECIAL    SENSE.  381 

bodv  articulates  with  the  malleus  and  the  long  process  by  means 
of  a  rounded  process.  The  os  orbiculare  (processus  lenticularis) 
articulates  with  the  head  of  the  stapes. 

3.  Stapes,  or  stirrup,  has  a  head  (capitvlwm  stapedis), 
neck,  two  branches  or  crura  (crura  anterius  et  crura  poste- 
riiis).  which  unite  into  a  cross-piece  or  bast'  (basis  stapedis) 
The  neck  has  inserted  into  it  the  stapedius  muscle,  and  the  base 
is  fitted  to  the  fenestra  ovalis. 


Fig.  137. 


The  auditory  ossicles.  A.  G.,  external  meatus;  M,  membrana  tym- 
pani ;  n,  handle  of  the  malleus  and  its  short  process  (p);  h,  head  of 
the  malleus;  a,  incus;  K,  its  short  process,  with  its  ligament;  I,  long 
process;  *,  os  orbiculare;  »S',  stapes;  -lJ",  Ax,  the  axis  of  rotation  of 
the  ossicles,  shown  in  perspective;  t,  line  of  traction  of  the  tensor 
tympani.  The  other  arrows  show  the  movements  of  the  ossicles  when 
the  tensor  contracts.     (Boennhnj.) 

Ligaments    of    the    ossicles    (ligamenta    ossiculorum    audi- 
tus)  : — 

Anterior  ligament  of  the  malleus  (ligamentum  mallei  anterius), 
extends  from  the  neck  of  the  malleus  to  the  outer  wall  of  the  tympanum; 

Superior  Ligament  of  the  malleus — ligamentum  mallei  sus|icn- 
sorium  [ligamentum  mallei  superius),  suspends  the  head  of  the  malleus 
to  tin-  roof; 

Posterior  ligament  of  the  incus  (ligamentum  incudis  posterius), 
attaches  the  shorl  process  to  the  posterior  wall; 

Superior  ligament  of  the  incus  (ligamentum  incudis  superius), 
]-  merely  ■■>  told  of  mucous  membrane;  while  tin-  inner  surface  ami  cir- 


382        *  HUMAN    ANATOMY. 

cuniference  of  the  base  of  the  stapes  is  connected  to  the  margin  of  the 
oval  window  by  means  of  the  annular  ligament  of  the  stapes  (ligamen- 
tum  annulare  baseos  stapedis) . 

Muscles. — The  tensor  tympani  and  stapedius. 

Tensor  t}rmpani  (already  described). 

Stapedius  (m.  stapedius)  arises  from  the  hollow  of  the 
pyramid  on  the  inner  wall,  and  its  tendon  is  inserted  into  the 
neck  of  the  stapes.  It  is  the  smallest  muscle  in  the  human  body. 
Nerve  from  the  tympanic  branch  of  facial. 

Arteries: — 

Tympanic  branch   of  internal  maxillary; 
Stylomastoid  branch  of  posterior  auricular; 
Petrosal  branch  of  middle  meningeal; 
Tympanic  branch  from  internal  carotid; 
Branch  from  ascending  pharyngeal. 

Veins  accompany  the  corresponding  arteries  and  empty 
into  middle  meningeal  and  pharyngeal. 

Nerves: — 

Chorda  tympani,  from  the  facial,  enters  the  iter  chorda? 
posterius,  crosses  the  tympanum  between  the  long  process  of 
the  incus  and  the  handle  of  malleus,  and  makes  its  exit  at  the 
iter  chordae  anterius; 

Tympanic  branch  of  glossopharyngeal  (Jacobson's  nerve) 
enters  the  floor,  supplies  the  fenestras  and  mucous  membrane  of 
tympanum  and  Eustachian  tube ; 

Tympanic  branch  from  facial  to  the  stapedius; 

Branch  from  the  otic  ganglion  to  the  tensor  tympani. 

The  tympanic  plexus  is  formed  upon  the  surface  of  the 
promontory,  from  the  following  nerves: — ■ 

Jacobson's  nerve,  tympanic  branch  of  the  glossopharyngeal; 
Branch  of  the  superficial  petrosal,  from  the  facial; 
Branches  from  the  carotid  plexus  of  the  sympathetic. 

INTERNAL     EAR,     OR    LABYRINTH. 

The  internal  ear  (auris  interna),  the  essential  part  of  the 
organ  of  hearing,  consists  of  three  complex  cavities  within  the 
petrous  portion  of  the  temporal  bone,  rilled  with  fluid,  the 
perilymph,  and  containing  a  membranous  sac  filled  also  with 
fluid,  the  endolymph,  which  receives  the  distributions  of  the 
auditory  nerve. 


ORGANS    OF    SPECIAL    SENSE.  383 

Its  divisions  are : — 

(Vestibule, 
Semicircular  canals, 
Cochlea ; 

f  Utricle, 

,  ,.         i  Saccule, 

Membranous  portion,  <j  8emicircular  canals> 

[  Cochlea. 

Vestibule  (vestibulum) ,  is  a  common  cavity  of  communi- 
cation between  the  bony  parts  of  the  internal  ear.  It  is  sit- 
uated between  the  tympanum  without,  the  cochlea  behind,  and 
tli.  semicircular  canals  in  front,  and  measures  one-fifth  of  an 
inch  in  its  anteroposterior  and  vertical  diameters,  and  less  from 
without  inward.     It  presents: — 

Fenestra  ovalis  (fenestra  vestibuH)  on  its  outer  wall,  closed 
by  the  stapes  and  its  ligament; 

Fovea  hemispherica  (recessus  spharicus) ,  a  circular  de- 
pression on  its  inner  wall  for  the  saccule,  and  perforated  by 
the  macula  cribrosa  (macula  cribrosa  media),  for  the  vestibular 
filaments  of  the  auditory  nerve; 

Orifice  of  the  aqucechictus  vestibular,  on  the  inner  wall  for 
the  transmission  of  a  small  vein; 

Eminent ia  pyramidalis,  a  vertical  ridge  on  the  inner  wall 
separating  the  two  fovea?. 

Fovea  semielliptica  (recessus  ellipticus),  in  the  roof  lodges 
the  utricle. 

SemicircuIiAB  canals  (canales  semicirculares  ossei)  are 
three  canals,  forming  each  two-thirds  of  a  circle,  one-twentieth 
of  an  inch  in  diameter,  and  named,  from  their  position,  the 
superior,  posterior  and  external.  They  are  placed  nearly  at 
right  angles  to  each  other  and  open  into  the  vestibule  by  live 
apertures — two  extremities  uniting  to  form  one. 

The  superior  (canalis  semicircularis  superior)  and  poste- 
rior {canalis  semicircularis  posterior)  arc  both  vertical,  the 
former  being  more  anterior. 

The  externa]  {canalis  semicircularis  lateralis)  is  placed 
horizontally,  its  arch  directed  backward. 

Ampulla,  arc  the  dilated,  flask-shaped  extremities  of  the 
tubes,  and  aro  about  one-tenth  of  an  inch  in  diameter. 

Tin:  cochlea  resembles  closely  a  common  snail's  shell, 
placed  with  the  base  corresponding  to  the  bottom  of  the  meatus 
auditoriue  internus,  and  its  apes  directed  outward  and  forward. 

It    consists    of    two    parallel    tubes    one    and    one-half    incbes    in 


384 


HUMAN    ANATOMY. 


length,  one-tenth  of  an  inch  in.  diameter,  wound  spirally  for 
two  and  one-half  turns  around  a  central  pillar — the  modiolus. 

The  modiolus,  or  columella  (basis  modioli),  is  broad  at  the 
base,  but  tapers  gradually  toward  the  apex,  where  it  terminates 
within  the  last  turn  or  cupola  in  the  infundibulum,  a  funnel- 
shaped  lamina  of  bone.  Its  interior  is  traversed  by  numerous 
canals  for  vessels  and  nerves,  one  of  which — the  canalis  centralis 
modioli — runs  nearly  the  whole  length  and  transmits  the 
arteria  centralis  modioli. 


■     FIG.  138. 

Organ  of  Corti.  AT,  cochlear  nerve;  K,  inner  and,  P,  outer  hair- 
cells;  n,  nerve  fibrils  terminating  in  P;  a,  a,  supporting  cells-;  d,  cells 
in  sulcus  spiralis;  z,  inner  rod  of  Corti;  Mb,  Corti,  membrane  of  Corti, 
or  the  memibrana  tectoria;  o,  the  membrana  reticularis;  H,  O,  cells 
filling  up  the  space  near  the  outer  wall.     (Bocnning.) 

Lamina  spiralis,  the  partition  between  the  two  tubes,  con- 
sists of  two  thin  laminas  of  bone  filled  with  cancellous  tissue — 
lamina  spiralis  ossea — projecting  from  the  modiolus  half-way  to 
the  outer  wall,  the  lamina  being  completed  by  the  membrana 
basilaris.  The  osseous  lamina  terminates  in  the  cupola  in  a 
hook-like  process — the  hamulus  (hamulus  lamince  spiralis). 

The  spiral  canal,  between  the  modiolus  and  the  outer  wall, 
is  divided  by  the  lamina  spiralis  ossea  and  membrana  basilaris 
into  two  canals,  or  scalce — the  upper  scala  vestibuli,  and  the 
lower  scala  tympani. 


ORGANS    oF    SPECIAL    SENSE.  335 

The  first  turn  of  the  spiral  canal  presents  three  openings : — 

1.  Fenestra  rotunda,  a  circular  aperture  communicating 
with  the  tympanum,  and  closed  by  the  membrana  tympanum 
secundaria. 

'2.  Fenestra  oralis,  an  oval  opening,  communicating  with 
the  vestibule. 

:'..  Aquaeductus  cochlearis  (apertura  externa  canaticuli 
cochlea),  a  Bmall  foramen  opening  on  the  inferior  surface  of  the 
petrous  portion  of  the  temporal  bone,  and  transmitting  a  small 
vein  from  the  cochlea  to  the  jugular  vein. 

8cala  vestibuli,  begins  at  the  fenestra  ovalis,  and  ascends 
in  a  spiral  course  above  the  lamina  spiralis  and  membrana 
basilaris,  to  communicate  with  the  scala  tympani,  through  the 
helicotrema  within  the  vestibule.     It  contains  perilymph. 

Scala  tympani  begins  at  the  fenestra  rotunda,  and  ascends, 
in  a  spiral  course  below  the  scala  vestibuli,  from  which  it  is 
separated  by  the  osseomembranous  lamina.  It  also  contains 
perilymph. 

11 1'licotrema  is  an  opening  within  the  cupola,  by  which  the 
two  scalae  communicate.  It  is  formed  by  a  deficiency  of  the 
osseous  lamina. 

Canalis  spiralis  modioli  is  a  small  canal  which  winds 
around  the  modiolus  at  the  attachment  of  the  osseous  laminae. 
Jt  contains  a  gangliform  swelling — ganglion  spirale  (ganglion 
spiral e  cochlea) — from  which  nerves  pass  to  the  organ  of  Corti. 

The  membranous  labyrinth  (labyrinthus  membrana- 
n  us)  corresponds  closely  to  the  osseous,  the  vestibule  consisting 
of  two  membranous  sacs — the  utricle  and  saccule — communicat- 
ing with  each  other,  and  the  former  receiving  the  five  openings 
of  the  membranous  semicircular  canals,  the  latter  communicat- 
ing with  the  membranous  cochlea  through  the  canalis  reuniens 
(il ml  us  reuniens  \IIenseni\).  The  membranous  labyrinth  is 
Burrounded  everywhere  with  perilymph  (perilympha) }  filled  with 
endolymph  (endolympha  | .  and  is  composed  of  three  coats — an 
outer  fibrous  layer,  middle  or  tunica  propria  and  inner  epithe- 
lial Iay<r. 

Utricle  {utriculus),  the  larger  of  the  two,  is  an  elliptical 
sac  lodged  in  the  fovea  hemielliptica.  The  semicircular  canals 
communicate  with  it  by  five  openings.  Its  wall  is  flic  thickest 
near  tin-  crista  vestibuli,  where  the  filaments  of  the  nerve  enter, 
the  macula  acustica. 

Saccule    (sat  ruins) .    is    a    bcniispberical    sac    lodged    in    the 

fiemispherica.     It  communicates  with  the  cochlea  through 

a   Bmall  duct      the  canalis   reunicn-. 


386  HUMAN    ANATOMY. 

The  otoliths,  or  otoconia,  are  small  masses  of  crystals  of 
lime  carbonate,  contained  in  the  inner  wall  of  the  ntricle  and 
saccule  opposite  the  distribution  of  the  nerves. 

Semicircular  Canals  (ductus  semicircular  es) . — These  are 
three  membranous  tubes  corresponding  exactly  in  shape,  num- 
ber and  form  with  the  bony  canals  in  which  they  are  contained.  < 
They  are  surrounded  everywhere  with  perilymph,  except  at  the 
ampullae,  where  they  are  in  contact  with  the  bony  canals.  The 
inner,  or  epithelial,  layer  of  the  membrane  in  the  ampullae  is 
covered  with  columnar  ciliated  epithelium — auditory  hairs. 

The  membranous  cochlea  begins  at  the  base  and  ascends 
in  a  spiral  course  within  the  osseous  cochlea  to  terminate  in  the 
cupola.  It  includes  only  the  canalis  cochlea? — a  part  of  the 
scala  vestibular.  As  before  stated,  the  membrana  basilaris  ex- 
tends from  the  margin  of  the  lamina  spiralis  ossea  to  the  outer 
wall  of  the  cochlea,  dividing  the  cavity  into  the  two  scalas — the 
scalae  vestibular  above,  the  scalae  tympani  below.  The  former  is 
again  subdivided  by  the  membrane  of  Keissner  (membrana 
vestibularis  [Reissneri])  into  two  parts,  the  outer  of  which 
forms  the  canalis  cochlear,  or  scala  media— the,  membranous 
cochlea  proper — on  the  floor  of  which  is  the  organ  of  Corti 
(organon  spirale  [Cortii~])  covered  by  the  membrana  tectoria. 
The  scalae  are  lined  with  periostium  and  filled  with  perilymph. 
The  scala  tympani  ends  at  the  fenestra  rotunda,  but  the  scala 
vestibula  communicates  freely  with  the  vestibula. 

Limbus  lamina?  spiralis  is  the  periosteal  margin  of  the 
lamina  spiralis  ossea,  and  consists  of  an  upper  lip — the  labium 
vestibulare — and  a  lower  lip — the  labium  tympanicum — sepa- 
rated by  a  groove — the  sulcus  spiralis. 

Membrana  basilaris  extends  from  the  labium  tympanicum 
to  the  outer  cochlear  wall,  to  which  it  is  attached  by  the  liga- 
mentum  spirale  of  Henle. 

Membrane  of  Beissner  arises  from  the  middle  of  the  vestib- 
ular lamina  and  passes  obliquely  at  an  angle  of  40  degrees  to 
the  outer  cochlear  wall,  separating  the  canalis  cochleae  from  the 
scala  vestibula. 

Canalis  cochlea?  extends  as  a  spiral  sac  closed  at  both  ends 
through  the  osseous  cochlea,  and  contains  the  most  important- 
part  of  the  labyrinth — the  ultimate  distribution  of  the  auditory 
nerve  in  the  organ  of  Corti.  It  is  triangular  on  section,  the 
membrana  basilaris  forming  the  base,  the  membrane  of  Eiessner 
the  inner  side,  and  the  periosteum  of  the  cochlea  its  outer  side. 

Membrana  tectoria,  or  membrane  of  Corti,  is  attached  to 
the  vestibular  surface  of  the  spiral  lamina,  in  close  proximity  to 


ORGANS    OF    SPECIAL    SENSE.  387 

the  attachment  of  the  membrane  of  Reissner,  and  arches  over  to 
the  outer  cochlear  wall,  inclosing-  the  organ  of  Corti,  but  not  in 
contact  with  it. 

Organ  of  Corti  consists  of  two  sets  of  pillars — the  inner 
and  outer  rods  of  Corti — extending  upward  upon  the  vestibular 
surface  of  the  membrana  basilaris,  and  forming  a  series  of 
arches.  Between  the  bases  of  the  arches  is  the  zona  arcuata. 
There  are  over  three  thousand  arches,  and  within  them  is 
formed  a  tunnel  extending  the  entire  length  of  the  lamina 
spiralis  terminating  at  the  hamular  process. 

Inner  roils  of  <  'urfi  rest  upon  the  basilar  membrane.  Their 
upper  extremities  resemble  the  proximal  extremity  of  the  ulna, 
and  each  has  on  its  inner  side  a  row  of  epithelial  cells — the 
inner  linir  cells. 

Outer  rods  of  Corti  are  attached  in  a  similar  manner  at 
the  bases,  and  their  extremities  each  resemble  the  head  and  bill 
of  a  swan,  the  former  fitting  into  the  cavity  in  the  inner  rods. 
On  the  outer  side  are  four  rows  of  ciliated,  cells — the  outer  hair 
cells. 

Reticular  membrane,  lamina  reticularis  or  membrane  of 
Kolliker,  is  a  delicate  complex  network  of  phalanges — fiddle- 
shaped  structures — extending  from  the  inner  rods  to  the  ex- 
ternal row  of  the  outer  hair  cells. 

Tut;  internal  auditort  canal  is  a  short  canal  about 
one-third  of  an  inch  in  length,  extending  outward  from  the 
meatus  auditorius  interims  (meatus  acustiens  internus),  on  the 
posterior  Burface  of  the  petrous  portion  of  the  temporal  hone. 
to  terminate  at  a  vertical,  perforated  plate — the  lamina  crih- 
rosa.  This  plate  is  divided  by  a  horizontal  ridge — the  falciform 
cresl  {crista  falciformis) — into  a  lower  and  upper  portion.  The 
lower  is  perforated  by  numerous  foramina  for  passage  of  the 
auditory  artery  and  branches  of  the  auditory  nerve,  some  of 
which  are  arranged  into  a  spiral-shaped  depression,  called  the 
tracius  spiralis  foraminosus;  the  upper  has  one  large  open- 
ing-—the  commencement  of  the  aqueductus  Fallopii  (canalis 
facialis)   for  portio  dura,  or  seventh  nerve. 

Auditory  Nerve  (n.  acusticus). — The  auditory  nerve  enters 
die  internal  auditory  meatus  in  company  with  the  facial,  and 
:it    the    bottom    divides    into    two    branches — the    vestibular    and 

sochlear. 

Vestibular  nerve  (n.  vestibularis)  subdivides  into  three 
branches,  as  follow 

Superior,  distributed  <<>  the  utricle  and  ampullae  of  the  superior 
find  external  semicircular  canals; 


388  HUMAN    ANATOMY. 

Middle,  enters  the  bottom  of  the  fovea  hemispherica,  and  is  dis- 
tributed to  the   saccule;    and  the 

Inferior  is  distributed  to  the  ampulla  of  the  posterior  simicircular 
canal. 

Cochlear  nerve  (n.  cochlearis) ,  ascends  in  the  canals  in  the 
modiolus,  and  divides  into  numerous  branches  which  pass  be- 
tween the  plates  of  the  lamina  spiralis  ossea,  forming  a  plexus 
which  contains  the  ganglia  spirale  (ganglion  spirale),  from 
which  filaments  are  distributed  to  the  outer  and  inner  hair 
cells  of  the  organ  of  Corti. 

Arteries,  of  Labyrinth: — 

Internal  auditory,  from  the  basilar,  divides  into  vestibular 
and  cochlear  branches.,  which  accompany  the  corresponding 
nerves ; 

Stylomastoid,  from  the  posterior  auricular,  enters  through 
the  stylomastoid  foramen. 

THE  TONGUE.1 

The  tongue  (lingua)  is  the  organ  of  the  sense  of  taste,  and 
lies  in  the  floor  of  the  mouth.  It  is  composed  of  a  mass  of 
muscles,  the  free  surface  of  which  is  entirely  invested  with 
mucous  membrane.     It  consists  of  three  parts: — 

Base,  or  root  (radix  Ungues),  attached  to  the  hyoid  bone, 
the  epiglottis  and  the  soft  palate; 

Body  (corpus  linguae),  the  back  or  dorsum  of  which  is 
marked  by  a  median  line  or  raphe,  terminating  behind  in 
a  cavity— the  foramen  cecum  (foramen  caecum  lingua?  [Mor- 
gagnii]). 

Apex  (apex  lingua?),  or  tip,  narrow  and  pointed,  directed 
forward. 

The  mucous  membrane  (tunica  mucosa  Ungual)  resembles 
skin,  consisting  of  a  corinm  or  mucosa,  containing  numerous 
papilla?,  and  covered  with  epithelium.  The  papilla?  (papilla? 
lingua?)  are  most  numerous  over  the  anterior  two-thirds  of  the 
dorsum,  and  consist  of  three  varieties : — 

Circumvallate  or  papilla?  maxima?  (papilla?  vallata?) ,  the 
largest,  about  ten  in  number,  about  one-twelfth  inch  wide,  are 
arranged  at  the  back  part  of  the  dorsum  like  the  letter  V  with 
the  apex  directed  backward; 

Fungiform  or  papilla?  media?  (papilla?  fungiformes  et 
papilla?  lenticulares) ,  the  medium,  are  scattered  over  the  organ, 
especially  at  the  tips  and  sides; 

1  Vide  Lingual  Muscles,  page   135. 


ORGANS   OF    SPECIAL    SENSE.  389 

Filiform,  conical  or  papillae  minima3  (papUlce  conicce  et 
papilla  fUiformes),  the  smallest,  are  distributed  over  the  ante- 
rior two-thirds  of  the  dorsum. 

Mucous  and  serous  glands  and  simple  papilla?,  such  as  are 
found  in  the  skin,  are  also  present. 

Taste  buds,  minute,  flask-shaped  bodies,  about  one-three- 
hundredths  of  an  inch  in  length,  are  situated  in  the  circumval- 
late  and  fungiform  papilla. 

Arteries  are  branches  of  the  lingual,  facial  and  ascending 
pharyngeal. 

1.  Nerves. — Hypoglossal,  the  principal  motor  nerve. 

2.  Lingual  branch  of  glossopharyngeal,  the  special  nerve  of 
taste. 

3.  Lingual  branch  of  the  trifacial,  to  sides  and  anterior 
part;  nerve  of  common  sensation. 

4.  Chorda  tympani,  probably  nerve  of  special  sense. 

5.  Superior  laryngeal,  filaments  from  its  internal  branch 
to  the  base. 

THE    SKIN    AND    APPENDAGES. 

The  skin  (integumentum  commune),  besides  being  the  spe- 
cial organ  of  the  sense  of  touch,  is  an  absorbing  and  excretory 
organ,  and  protects  the  underlying  structures. 

It  consists  of  two  layers — the  epidermis  or  cuticle,  and  the 
derma  or  true  skin.  The  appendages  are  the  nails,  hair,  sudorif- 
erous and  sebaceous  glands,  and  their  ducts. 

The  epidermis,  or  cuticle,  is  an  epithelial  structure  con- 
sisting of  four  layers  : — 

1.  Bete  MalpigTm,  the  deepest  layer,  in  contact,  with  the  corium,  is 

composed  <>f  several   layers  of  round  or  polyhedral  epithelial  cells.     This 
layer  is  pigmented  in  the  negro  and  other  dark  races. 

2.  Granular  layer,  is  a  single  layer  of  compressed,  spindle-shaped 
cells. 

'■',.   St  rut  am   I  uciilii  m .  is   -till    mure  (-(impressed   into  scales. 
4.  Stratum  corneum,  several  layers  of  horny  scales. 

The  derma,  corium,  or  true  skin,  has  two  Layers,  the  reticular 
or  deeper,  and  the  papillary  or  superficial. 

Reticular  layer  {stratum  reticulare)  is  composed  of  inter- 
lacing bands  of  white  fibrous  tissue,  mixed  with  yellow  elastic 
libers,  and  some  iinstrialed  muscular  fibers  where  hairs  are 
found,    together  with    blood    vessels,  lymphatics  and   nerves. 

Papillary  layer  (stratum  papUlare)  is  covered  with  minute, 
vascular,  highly  sensitive  elevations-  the  papillae — from  one- 
one-hundredth    to  one-two-hundred-and-fiftieth   of   an    inch    in 


390  HUMAN   ANATOMY. 

diameter.  These  papillae  are  in  places  arranged  into  parallel 
curved  ridges,  and  have  in  the  most  sensitive  situations  some 
one  of  the  peripheral  end  organs  (already  described)  added 
to  their  structure. 

Nails  (ungues)  are  horny  plaques  of  modified  epidermis, 
firmly  adapted  to  the  derma  on  the  dorsal  surfaces  of  the 
termiual  phalanges.  Each  nail  is  firmly  implanted  by  its  root 
(radix  unguis)  into  a  fold  of  skin. 

The  matrix  (matrix  unguis)  is  the  derma  beneath  the 
body,  which  is  vascular  and  highly  sensitive. 

The  lunula,,  on  account  of  its  crescentic  shape,  is  the  white, 
less  vascular  portion  of  the  matrix  near  the  root. 

Haies  (pili)  are  a  cylindrical'  modification  of  the  epider- 
mis, and  consist  of  a  root  imbedded  in  the  skin,  a  shaft  and  a 
point. 

Eoot  (radix  pili)  is  lodged  in  a  pouch-like  involution  of 
epidermis — the  hair  follicle  (follicidus  pili).  This  is  composed 
of  an  inner  or  cuticular  and  an  outer  or  dermic  layer,  and  pre- 
sents at  the  bottom  a  vascular  papilla,  on  which  the  hair  rests, 
and  from  which  it  grows. 

Shaft  (scapus  pili)  consists  of  a  pith  or  medulla  (sub- 
stantia medullaris  pili)  in  the  center,  surrounded  by  a  fibrous 
part  containing  pigment,  and  covered  with  a  layer  of  scaly 
epithelium. 

Point  contains  the  two  latter  elements,  but  has  no  medulla. 

Sebaceous  glands  (glandulce  sebacece)  are  minute,  gland- 
ular bodies,  situated  in  the  substance  of  the  corium,  and  each 
opening  by  a  single  duct  into  a  hair  follicle,  or  upon  the  sur- 
face of  the  skin.  They  are  most  abundant  where  hairs  are 
found.     The  Meibomian  glands  in  the  eyelids  are  the  largest. 

Sudoriferous  or  sweat  glands  (glandulce  sudoriferce)  are 
minute,  reddish,  glandular  bodies,  situated  usually  in  the  sub- 
cutaneous connective  tissue,  each  consisting  of  a  single  con- 
voluted tube.     Each  gland  opens  on  the  surface  of  the  skin. 


SURGICAL  ANATOMY. 


THE    TRIANGLES    OF    THE    NECK. 


The  general  outline  of  the  neck  is  somewhat  quadrilateral. 
Bounded  in  front  by  the  median  line,  behind  by  the  trapezius 
muscle,  above  by  the  lower  border  of  the  body  of  the  maxilla 
and  below  by  the  clavicle.  It  is  divided  by  the  sternomastoid 
muscle  running  obliquely  through  it  into  two  large  triangles, 
an  anterior  and  a  posterior  triangle.  These  are  again  sub- 
divided by  the  crossing  of  the  omohyoid  muscle  into  two  smaller 
triangles  each.  The  anterior  into  the  superior  and  interior 
carotid  triangles,  and  the  posterior  into  the  occipital  and  sub- 
clavian triangles.  The  digastric  nmscle,  at  the  upper  part  ot 
the  anterior  triangle,  separates  a  triangular  space  called  the 
submaxillary  triangle.  n„«™. 

The  (interior  triangle  of  the  neck  is  bounded  as  follows.— 
Front,  median  line  of  the  neck ; 

Behind,  anterior  border  of  the  sternomastoid  muscle ; 
Vl.uve.   lower  border  of  the  body  of  the  lower  jaw  and  a 
line  from  its  angle  to  the  mastoid  process,  forming  the  base  ot 
the  triangle;  . 

Below,  the  top  of  the  sternum,  forming  the  apex. 
The  floor  is  formed  by  the  sternohyoideus,  sternothy- 
riodeus,  thvrohvoideus,  inferior  and  middle  constrictors  of  the 
pharynx,  the  anterior  belly  of  the  digastricus,  the  mylohyoideus, 
stylonyoideus,  and  hyoglossus  muscles.  The  roof  is  formed  by 
the  skin,  superficial  fascia,  platysma  myoides,  and  deep  iascia. 

The  inferior  carotid  triangle  is  the  most  inferior  subdivi- 
sion of  the  anterior  triangle,  and  is  bounded  as  follows:— 
Front,  median  line  of  the  neck; 
Behind,  anterior  border  of  the  sternomastoideus ; 
Above,  anterior  belly  of  the  omohyoideus; 
Below,  the  apex  of  "the  anterior  triangle. 
It  contains  the  following  structures:— 
Thyroid  gland  and  lower  part  of  the  trachea  and  Larynx; 
Inferior  thyroid  and  common  carotid  arteries; 
Inferior  thyroid  and   internal  jugular  reins; 
Pneumogastric,  recurrenl  laryngeal,  descendens  noni,  com- 
municans  noni  and  sympathetic  nerves. 

(391) 


392  HUMAN    ANATOMY. 

The  superior  carotid  triangle  is  the  middle  subdivision  of 
the  anterior  triangle  of  the  neck,  and  has  the  following  bound- 
aries : — 

Above,  posterior  belly  of  the  digastricus; 

Below,  anterior  belly  of  the  omohyoideus; 

Behind,  anterior  border  of  the  sternomastoideus. 

It  contains  the  following  structures : — 

Termination  of  the  common  carotid; 

The  internal  carotid; 

The  external  carotid,  and  the  following  branches: — 

Superior  thyroid,  lingual,  facial,  ascending  pharyngeal 
and  occipital; 

The  internal  jugular  vein,  and  the  following  tributaries : — 

Lingual,  facial,  superior  thyroid,  pharyngeal  and  occa- 
sionally the  occipital; 

The  pneumogastric,  superior  laryngeal,  external  laryngeal, 
descendens  noni,  spinal  accessory,  hypoglossal  and  sympathetic 
nerves. 

The  submaxillary  triangle  is  the  most  superior  of  the  sub- 
divisions of  the  anterior  triangle,  and  has  the  following  bound- 
aries : — 

Above,  the  lower  border  of  the  body  of  the  jaw  and  the 
imaginary  line  behind ; 

In  front,  the  median  line  of  the  neck ; 

Behind,  the  posterior  belly  of  the  digastricus. 

It  contains  the  following  structures : — 

External  carotid,  internal  carotid,  facial,  submental,  mylo- 
hyoidean  arteries; 

The  internal  jugular,  the  commencement  of  the  external 
jugular,  branches  of  the  anterior  jugular  and  the  facial  vein 
and  its  branches; 

The  inframaxillary  branches  of  the  facial  nerve,  the  ascend- 
iug  branches  of  the  superficial  cervical  nerve,  and  the  pneumo- 
gastric and  glossopharyngeal  and  mylohyoid  nerves; 

Portions  of  the  parotid  and  submaxillary  glands,  and  also 
submaxillary  lymphatic  glands  and  vessels. 

The  posterior  triangle  of  the  neck  occupies  the  space  be- 
hind the  posterior  border"  of  the  sternomastoideus,  and  is 
bounded  as  follows : — 

Front,  posterior  border  of  the  sternomastoideus; 

Behind,  anterior  border  of  the  trapezius; 

Below,  upper  border  of  the  middle  third  of  the  clavicle, 
forming  its  base; 

Above,  the  occiput,  forming  the  apex. 


SURGICAL    ANATOMY. 


393 


Its  floor  is  formed  from  above  downward,  by  the  following 
muscles : — 

Splenius  capitis,  levator  anguli  scapuli,  scalenus  medius, 
scalenus  posticus,  and  the  upper  portion  of  the  serratus  magnus. 

Its  roof  is  formed  by  the  superficial  and  deep  fascia  and 
below  by  the  platysma  myoides. 


FIG.  139. 
Triangles  of  the  neck.     (Bocnning.) 

It  contains  the  following  structures: — 

'Jdic  transversalis  colli  artery  and  vein; 

Spinal  accessory  and  superficial  plexus  of  the  cervical 
nerve ; 

Lymphatic  glands  and  vessels. 

The  subclavian  triangle,  or  the  inferior  division  of  the 
posterior  triangle,  is  bounded — 


394  HUMAN    ANATOMY. 

In  front  by  the  margin  of  the  sternomastoideus,  behind  by 
the  posterior  belly  of  the  omohyoideus,  below  by  the  clavicle. 

It  contains  the  following  structures : — 

The  subclavian,  transversalis  colli  and  transversalis  humeri 
or  suprascapular  arteries; 

The  transversalis  colli,  suprascapular  and  external  jugular 
veins ; 

The  descending  branches  of  the  superficial  cervical  plexus 
and  the  brachial  plexus  of  nerves ; 

Lymphatic  nerves  and  vessels. 

Triangle  in  Front  of  the  Elhoiu-joint. 

Bounded — 

Externally,  by  supinator  longus; 

Internally,  by  pronator  radii  teres; 

Base,  above,  by  a  line  (imaginary)  drawn  through  the  con- 
dyles; 

Apex,  below,  by  crossing  of  supinator  longus  and  pronator 
radii  teres. 

It  is  covered  in  by  skin,  superficial  fascia  and  bicipital 
fascia;  the  floor  is  formed  by  oblique  fibers  of  the  supinator 
brevis  and  lower  part  of  brachialis  anticus  muscles. 

It  contains: — 

From  within  outward,  median  nerve,  brachial  artery, 
vense  comites,  biceps  tendon  and  musculospiral  nerve. 

Scarpa's  Triangle   (trigonum  femorale) 

is  a  large  triangular  space  situated  in  the  upper  part  of  the 
anterior  surface  of  the  thigh,  through  which  the  femoral  vessels 
descend.     It  is  bounded — 

Externally  by  sartorius,  internally  by  adductor  longus, 
above  by  Poupart's  ligament;  below,  apex  is  formed  by  crossing 
of  bounding  muscles. 

It  is  covered  in  by  skin,  superficial  fascia,  cribriform  fas-- 
cia  and  fascia  lata,  and  its  floor  is  formed  by  the  following  from 
without  inward :  iliacus,  psoas,  pectineus  and  portion  of  adduc- 
tor brevis  muscles. 

It  contains: — ■ 

The  femoral  artery  (with  its  profunda  and  cutaneous 
branches),  inclosed  in  the  femoral  sheath,  femoral  vein  (joined 
by  profunda  and  long  saphenous  veins),  anterior  crural  nerve 
and  its  branches  [from  within  outward  being  vein,  artery  and 
nerve],  deep  lymphatic  glands  and  vessels  and  adipose  tissue. 


SI  RGICAL    ANATOMY. 


395 


Axilla. 

This  is  a  pyramidal  space  between   the  upper  and  lateral 

part  of  the  chest  and  the  inner  side  of  the  arm.    It  is  bounded — 

In  front,  by  the  pectoralis  major  and  minor  muscles;  be- 


FIG.  140. 

The  axilla.  1,  axillary  artery;  2,  brachial  artery;  3,  acromio- 
thoracic  artery;  4,  superior  thoracic  artery;  5,  subscapular  artery;  6, 
dorsalis  scapulae  artery;  7,  posterior  circumflex  atery;  8,  superior  pro- 
funda artery;  9,  posterior  thoracic  nerve;  10,  long  subscapular  nerve; 
11,  median  nerve;  12,  cephalic  vein;  13,  musculocutaneous  nerve;  14, 
teres  major  muscle.     {Boenning.) 


hind,  by  latissimus  dorsi,  teres  major  und  Bubscapularis;  inter- 
nally, by  the  upper  four  ribe  and  intercostal  and  upper  pari  of 

serratlM  magnilfl  muscles,  and    ils  apex    i-  directed    upward,  and 


396  HUMAN    ANATOMY. 

is  formed  by  the  space  between  the  first  rib,  clavicle  and  upper 
border  of  the  scapula,  and  its  base  by  the  skin  and  axillary 
fascia  stretched  across  between  the  lower  borders  of  the  pec- 
toralis  major  and  latissimus  dorsi  muscles. 

It  contains: — 

The  axillary  artery  and  vein  and  their  branches;  the 
brachial  plexus  of  nerves  and  the  branches  given  off  below  the 
clavicle;  branches  of  the  intercostal  nerves;  ten  or  twelve  lym- 
phatic glands  and  a  quantity  of  loose  adipose  and  areolar  tissue. 

Popliteal   Space. 

The  popliteal  space  is  a  lozenge-shaped  space  situated  at 
the  back  of  the  knee,  and  forms  the  ham.    It  is  bounded — 

Externally,  above  the  joint,  by  the  biceps;  below  the  joint, 
by  outer  head  of  gastrocnemius  and  plantaris;  internally,  above 
the  joint,  semitendinosus,  semimembranosus,  gracilis  and  sar- 
torius;  below  the  joint,  by  inner  head  of  the  gastrocnemius. 

It  is  covered  in  by  the  skin,  superficial  fascia  and  fascia 
lata. 

Its  floor  is  formed*  by  the  lower  part  of  the  posterior  sur- 
face of  the  femur,  the  ligamentum  posticum  Winslowi  and  the 
popliteus  muscle  and  its  fascia. 

It  contains: — ■ 

The  popliteal  artery  and  branches;  popliteal  vein  receiving 
the  external  saphenous  vein  (vein  to  the  outer  side)  ;  internal 
and  external  popliteal  nerves  and  branches;  articular  branch  of 
obturator  nerve ;  branch  of  small  sciatic  nerve ;  four  or  six 
lymphatic  glands,  and  a  quantity  of  adipose  and  areolar  tissue. 

ANATOMY    OP     HERNIA. 

Hernia  is  the  protrusion  of  any  part  of  a  viscus  from  its 
natural  cavity  through  the  inclosing  walls  of  the  cavity.  As 
usually  understood,  it  refers  to  the  protrusion  of  the  intestine 
or  mesentery,  or  both,  from  the  abdominal  cavity.  The  most 
common  forms  are : — 

External  or  oblique  inguinal  hernia; 
Internal  or  direct  inguinal  hernia; 
Femoral  hernia; 
Umbilical  hernia. 

1.  Oblique  inguinal  hernia  escapes  from  abdominal  cav- 
ity at  the  internal  abdominal  ring,  carrying  before  it  a  pouch 


si  RGICAL    ANATOMY 


;'.»; 


of  peritoneum,  descends  along  the  inguinal  canal  in  front  of 
the  cord,  and  emerges  at  the  external  opening.  The  anatomical 
parts  concerned  are  the  inguinal  canal,  with  its  interna]  and 
external  abdominal  rings,  the  transversals  fascia  (vide  Fascia), 
the  peritoneum  (vide  Peritoneum)   and  Poupart's  ligament. 


Fig.  141. 

Dissection  of  the  inguinal  canal:  A,  external  oblique;  B,  li,  in- 
ternal oblique;  0,  transversalis;  D,  conjoined  tendon;  E,  rectus  ab- 
dominis with  sheath  opened;  G,  fascia  transversalis;  //,  cremaster; 
/,   infundibular  fascia. 


The  mguvnal  or  spermatic  canal  is  about  one  and  a  half 
inches  in  length,  extending  from  the  internal  abdominal  ring 
to  the  externa]  abdominal  ring.  It  serves  for  the  passage  of 
the  spermatic  cord   in  the  male,  and   the  round   ligament  with 

essele  in  the  female.     Us  boundaries  are: — 


398  HUMAN    ANATOMY. 

In  front,  skin,  superficial  fascia,  the  aponeurosis  of  the 
external  oblique  muscle,  the  lower  border  of  the  internal  oblique, 
and  a  small  portion  of  the  cremaster  muscle; 

Behind,  the  fascia  transversalis,  the  conjoined  tendon  of 
the  transversalis  and  internal  oblique  muscles,  the  transversalis 
fascia,  and  subperitoneal  fat  and  peritoneum; 

Above,  by  the  arched  border  of  the  internal  oblique  and 
transversalis  muscles;  r~ 

Below,  by  the  connection  between  Poupart's  ligament  and 
the  transversalis  fascia. 

The  internal  abdominal  ring  (annulus  ingirinalis  abdomi- 
nalis)  is  an  oval  opening  in  the  transversalis  fascia  about  half 
an  inch  above  Poupart's  ligament,  midway  between  the  sym- 
physis pubis  and  the  anterior  superior  spinous  process  of  the 
ilium.     It  is  bounded — • 

Above  and  externally  by  the  arched  fibers  of  the  transver- 
salis muscle ;  below  and  internally  by  the  deep  epigastric  vessels. 

It  transmits  a  funnel-shaped  fascia  from  its  margins,  the 
in  fun  dib  uliform  fas  cia. 

The  external  abdominal  ring  (annulus  inguinalis  subcu- 
taneus)  is  a  triangular  opening  between  the  two  pillars  in  the 
aponeurosis  of  the  external  oblique  muscle,  to  the  outer  side  and 
just  above  the  spine  of  the  pubes.  It  is  about  half  an  inch 
wide  and  one  inch  long,  and  is  bounded — 

Above,  by  the  intercolumnar  fascia;  below,  by  the  spine 
and  crest  of  the  os  pubis,  and  on  either  side  by  the  pillars  or 
columns  of  the  ring  formed  by  the  free  margins  of  the  aponeu- 
rosis of  the  external  oblique. 

From  the  margins  of  the  external  abdominal  ring  arises 
the  intercolumnar  fascia. 

Poupart's  ligament,  or  the  femoral  arch  (ligamentum  in- 
guinale), is  the  rounded  lower  fibrous  margin  of  the  external 
oblique  muscle,  extending  between  the  anterior  superior  spine  of 
the  ilium  and  the  spine  of  the  pubes.  The  portion  of  the 
aponeurosis  which  is  inserted  into  the  pectineal  line  has  received 
the  name  of  Gimbernat's  ligament  (ligamentum  lacunare). 

The  triangular  ligament  or  ligament  of  Colles  (ligamen- 
tum inguinal  reflexum)  is  the  reflected  inner  portions  of  Gim- 
bernat's and  Poupart's  ligaments  attached  to  the  sheath  of  the 
rectus. 

The  epigastric  artery  (a.  epigastrica  inferior)  holds  a  very 
important  anatomical  relation  to  the  inguinal  canal  and  inter- 
nal abdominal  ring.  It  ascends  between  the  peritoneum  and 
transversalis  fascia  to  reach  the  sheath  of  the  rectus  muscle 


M  RGICAL    ANATOMY. 


39U 


Fig.  142. 

Deep  Femoral  Region-the  Femoral  Vessels,  etc.,  cut  across  as 
they  emerge  under  Pouparfs  ligament.  AC,  anttrior  crural  nerve; 
(  7  .dge  of  the  conjoined  tendon;  CK,  crural  ring;  K,  dotted  line  in- 
dicates the  course  of  the  deep  epigastric  artery;  FB,  femoral  sheath; 
Q  Gimbernafa  ligament;  TP,  llio-pectineal  ligament;  P,  Pouparfs 
ligament;  'PE,  pectineus  muscle.  This  muscle  rests  upon  the  pubic 
bone  and  is  covered  by  its  fascia— the  pectineal  fascia— which  is  some- 
what thickened  Immediately  beneath  Pouparfs  ligament,  where  it  is 
known  as  the  pubic  ligament  of  Cooper.  It  will  be  noticed  that  the 
femoral  sheath  is  divided  into  three  compartments:  the  outer  for  the 
femoral  artery;  the  middle  for  the  femoral  vein;  the  inner  (OR)  is1 
ti,.    .  rural   ring,   the  mouth   of  the  crural   canal.     (McQrath.) 


400  HUMAN    ANATOMY. 

along  the  inner   and  lower  margin   of   the   internal   ring  and 
beneath  the  spermatic  cord. 

The  coverings  of  oblique  inguinal  hernia  are : — 

(1)  Skin;  (2)  superficial  fascia ;  (3)  intercolumnar  fascia; 
(4)  cremaster  muscle  and  fascia;  (5)  fascia  transversalis,  or 
infundibuliform  fascia;  (6)  subserous  connective  tissue;  (7) 
peritoneal  sac. 

-  2.  Direct  inguinal  hernia  escapes  through  the  abdom- 
inal wall,  within  Hesselbach's  triangle,  internal  to  the  epigas- 
tric artery,  and  through  the  external  abdominal  ring,  pushing 
before  it  a  pouch  of  peritoneum. 

Hesselbach's  triangle  is  a  space  situated  at  the  lower  ante- 
rior part  of  the  abdominal  wall  on  either  side.  It  is  bounded 
as  follows: — 

Externally,  epigastric  artery; 

Internally,  the  outer  margin  of  the  rectus  abdominis 
muscle ; 

Below,  Poupart's  ligament,  forming  its  base.  The  struc- 
tures forming  the  abdominal  wall  at  this  cavity  are,  from  with- 
out inward: — 

1.  Skin; 

2.  Superficial  fascia; 

3.  Intercolumnar  fascia; 

4.  Conjoined  tendon  of  the  transversalis  and  internal  ob- 
lique ; 

5.  Fascia  transversalis; 

6.  Subserous  tissue; 

7.  Peritoneum. 

The  anatomical  parts  concerned  in  direct  inguinal  hernia 
are  the  same  as  those  in  the  indirect,  already  given.  The  cov- 
erings of  direct  inguinal  hernia  are  those  just  enumerated. 

3.  Femoral,  hernia  escapes  through  the  femoral  ring, 
carrying  before  it  a  pouch  of  peritoneum,  descends  through  the 
femoral  canal  and  emerges  through  the  saphenous  opening  in 
the  fascia  lata.  The  anatomical  parts  concerned  in  this  hernia 
are: — 

The  femoral  ring,  the  femoral  or  crural  canal,  the  septum 
crurale,  crural  sheath,  deep  crural  arch  and  the  saphenous 
opening. 

The  femoral,  or  crural  ring  (annuhis  femomlis) ,  is  an  oval 
opening,  about  an  inch  and  a  half  in  diameter,  larger  in  the 
female  and  situated  below  Pou'part's  ligament,  between  the 
inner  side  of  the  femoral  vein  and  the  margin  of  Gimbernat's 
ligament.     It  is  the  abdominal  opening  of  the  femoral  canal 


SURGICAL    ANATOMY.  401 

(canalis  femoralis),  and  it  is  closed  in  the  recent  state  by  the 
septum  crurale  and  a  small  lymphatic  gland.     It  is  bounded — 

In  front,  by  the  deep  femoral  arch  and  Pouparf s  ligament ; 

Behind,  by  the  pubes,  covered  by  the  pubic  portion  of  the 
fascia  lata  and  the  pectineus  muscle ; 

Externally,  by  the  femoral  vein,  from  which  it  is  sep- 
arated by  a  fibrous  septum ; 

Internally,  by  the  deep  femoral  arch,  Gimbernat's  ligament, 
the  transversalis  fascia  and  the  conjoined  tendon. 

The  femoral  canal  (canalis  femoralis)  is  a  space  from  a 
quarter  to  half  an  inch  in  length,  extending  from  Gimbernat's 
ligament  to  the  upper  margin  of  the  saphenous  opening. 
Bounded  above  by  the  femoral  ring  and  below  by  the  saphenous 
opening.  It  is  the  innermost  compartment  of  the  femoral 
sheath. 

Anterior  wall — transversalis  fascia,  separated  by  the  falci- 
form process  (margo  falciformis)  of  the  fascia  lata; 

Posterior  wall — iliac  fascia  and  pubic  portion  of  the  fascia 
lata; 

External  wall — fibrous  septum  of  the  femoral  vein; 

Internal  wall — Gimbernat's  ligament,  deep  crural  arch  and 
the  junction  of  the  iliac  and  tranversalis  fascia. 

The  septum  crurale  (septum  femorale  musculus)  is  a  layer 
of  dense  areolar  tissue,  supporting  small  lymphatic  glands  and 
closing  in  the  femoral  ring.  It  is  perforated  by  numerous  lym- 
phatic vessels,  and  forms  a  barrier  to  the  escape  of  hernia  at 
this  point. 

The  crural  or  femoral  sheath  (fascia  cruris)  is  a  prolonga- 
tion downward  of  the  fascia  lining  the  abdomen  (transversalis 
fascia  in  front,  iliac  fascia  behind  the  vessels),  closely  adhering 
to  the  femoral  vessels  to  about  an  inch  below  the  saphenous 
opening  (fossa  ovalis).  Its  upper  part  is  funnel-shaped  and 
it-  Lower  part  continuous  with  the  sheath  of  the  vessel.  It  is 
divided  by  septa  into  three  compartments;  in  the  outer  is  lodged 
the  femoral  artery;  the  middle  is  occupied  by  the  femoral  vein; 
and  the  innermost,  the  femoral  canal,  is  empty,  or  occupied  by 
a  Lymphatic  gland.  Its  outer  border  is  pierced  by  the  genito- 
c rural  nerve,  its  inner  by  the  internal  saphenous  vein. 

The  deep  femoral  arch  is  a  fibrous  thickening  of  the  trans- 
versalis fascia  which  forms  the  anterior  Avail  of  the  femoral 
gheath.     It  is*  also  known  as  the  deep  crural  arch. 

The  saphenous  apenmg  is  an  oval  aperture  of  half  an  inch 
in  width,  an  inch  and  a  half  in  length  in  the  upper  and  inner 
part  of  the  fascia  lata,  between  its  two  divisions,  the  iliac  and 

26 


402 


HUMAN    ANATOMY. 


pubic  portions.  It  is  bounded  externally  by  the  falciform 
process  of  Burns,  internally  by  the  pubic  portion  of  the  fascia 
lata,  which  curves  upward  behind  the  saphenous  vein.  The 
opening  is  covered  externally  by  the  cribriform  fascia  (fascia 
cribrosa)  and  the  skin. 

|  The  coverings  of  femoral  hernia  are: —     , 

1.  Skin; 

2.  Superficial  fascia; 

3.  Cribriform  fascia ; 


Hnttrhrlayrref 

V,.,  r™j  *"«■♦-  ~» 


Fig.  143. 
Male  perineum,   superficial  dissection.     (Lydston.) 

4.  Femoral  sheath,  crural  sheath,  or  fascia  propria; 

5.  Septum  crurale; 

6.  Subserous  connective  tissue; 

7.  Peritoneal  sac. 


ISCHIORECTAL    REGION    AND    PERINEUM. 

The  outlet  of  the  pelvis  is  a  lozenge-shaped  space  divided 
by  an  imaginary  line  drawn  in  front  of  the  anus,  transversely 
between  the  anterior  margin  of  the  tuber  ischii/into  two  parts, 
the  ischiorectal  region  behind  and  the  perineum  in  front. 

The  ischiorectal  region  contains  the  external  (m.  sphincter 
ani  externus)  and  internal  sphincters  (m.  sphincter  ani  inter* 


SURGICAL    ANATOMY. 


403 


mis),  the  corrugator  cutis  ani  and  the  ischiorectal  fossa  (fossa 
ischwrectalis) .  The  latter  is  a  pyramidal  cavity,  its  apex 
reaching  to  the  junction  of  the  obturator  and  anal  fascia  and 
its  l>ase  formed  by  the  skin.    It  is  bounded—. 

Behind,  by  the  edge  of  the  great  sacrosciatic  ligament  and 
gluteus  maximus  muscle;  internally,  by  the  levator  ani,  covered 
by  the  anal  fascia,  sphincter  ani  and  coccygeus  muscle;  exter- 
nally, by  the  tuber  ischii  and  obturator  fascia. 


Artfrj  of  Cerpat  Cavtnnmn 
0*r*at  Artorg  j/*  Pent* 


Aritry  f/  Buli. 
Zmttmal  PaJie  Arte 

C*rp*r*  dam 


FIG.  144. 
Male  perineum,    deep   dissection.      (Lytlston.) 

It    t  O/i  hi  ins; 

The  internal  pudic  artery,  nerve  and  veins  inclosed  in  the 
fa-rial  canal  or  canal  of  Alcock  ; 

The  inferior  hemorrhoidal  vessels  and  nerves; 
The  perineal  and    fourth  sacral  nerves;  and 
A  mass  of  areolar  tissue. 


PEEINEUM. 


The  perineum  is  the  triangular  space  between  the  amis  and 
Bcrotum  in  the  male,  and  between  the  aims  and  vulva  in  the 
female.  The  skin  is  dark,  thin,  and  supplied  with  sebaceous 
and  sudoriferous  glands  and  is  marked  by  middle  Line  or  raphe. 


404  HUMAN    ANATOMY. 

Fascia   of  the  Perineum. 

The  pelvic  fascia  {fascia  pelvis)  at  the  brim  of  the  pelvis 
is  continuous  with  the  transverse  and  iliac  fascia;  covers  sac- 
rum, pyriformis  muscle,  external  iliac  artery  and  sacral  nerves. 
It  forms  the  lateral  true  ligaments  of  the  bladder  {ligamenta 
puboprostatica  lateralia)  in  the  male,  and  {ligamenta  pubo- 
vesicalia  lateralia)  in  the  female.  It  also  forms  the  anterior  true 
ligament  of  the  bladder  {ligamentum  puboprostaticum  medium) 
in  the  male  {ligamentum  pubovesicale  medium,)  in  the  female. 
It  forms  arcus  tendinege  {arcus  tendineus  fascice  pelvis),  or 
white  line,  corresponding  to  division  of  pelvic  fascia  into  .two 
layers,  the  obturator  and  rectovesical  {fascia  diaphragmatis  pel- 
vis superior),  extending  from  pubis  to  spine  of  ischium,  from 
which  originates  the  levator  ani  muscle,  with  rectovesical  and 
ischiorectal  or  anal  fascia?  above  and  below  the  muscle  re- 
spectively. 

The  obturator  fascia  {fascia  obturatoria) ,  the  continuation 
of  the  pelvic  fascia,  incloses  the  pudic  vessels  and  nerve  in  a 
sheath,  covers  the  internal  obturator  muscle  and  forms  the  pos- 
terior layer  of  the  triangular  ligament. 

Bectovesical  or  visceral  layer  of  the  pelvic  fascia,  the  com 
tinuation  of  the  pelvic  fascia,  descends  into  the  pelvis  investing 
the  prostate  glaud  and  the  vesicoprostatic  plexus  of  veins,  the 
bladder  (forming  the  anterior  and  lateral  true  ligaments)  and 
the  rectum.     It  is  perforated  in  the  female  by  the  vagina. 

Superficial  perineal  fascia  {fascia  superficialis  perinei) 
consists  of  superficial  fat  layer  and  deep  membranous  layer,  the 
fascia  of  Colles.  The  former  is  continuous  with  subcutaneous 
layer  of  buttocks,  thigh,  and  labia,  and  posterior  to  anus  be- 
come continuous  with  tissue  of  ischiorectal  fossa.  The  superior 
laijer  passes  from  rami  of  pubis  and  ischium  to  the  tuberosity 
of  ischia,  covering  ischiocavernous  and  bulbourethral  muscles, 
and  becomes  continuous  with  the  deep  perineal  fascia. 

The  deep  perineal  fascia  (triangular  ligament  of  the  per- 
ineum— trigonum  urogenitale  or  diaphragma  urogenitale)  is  a 
strong  triangular  membrane  extending  between  the  rami  ischii 
et  pubis,  its  apex  attached  to  the  under  surface  of  the  sym- 
physis. It  is  often  described  as  consisting  of  two  layers,  the 
superior,  deep  or  posterior  layer  {fascia  trigoni  urogenitalis 
superior),  and  inferior,  anterior  or  superficial  layer  {fascia 
trigoni  urogenitalis  inferior) .  It  is  pierced  by  the  membranous 
urethra,  and  sends  a  fascia  surrounding  the  urethral  glands  to 
the  spongy  body.  In  the  female  it  is  weaker,  the  urethra  also 
pierces  it,  and  it  is  continuous  with  the  fascia  of  the  vagina. 


si  i;<;i<  Al.    ANATOMY. 


405 


Muscles  of   the   Perineum. 

Ischiocaveknosl's  (erector  penis)  arises  in  the  inner  sur- 
face of  the  tuberosity  of  the  ischium,  and  is  inserted  into  the 
side  and  under  surface  of  the  cms  penis.  In  the  female  there 
is  a  similar  insertion  into  the  clitoris.  It  serves  to  maintain 
the  organ  erect.    Nerve,  perineal. 

Erector  clitoridis  (m.  ischiocarernosus)  corresponds  to 
erector  penis  muscle  in  the  male,  but  smaller. 


Female  perineum:  .4,  anus;  IS,  bulbo-vaginal;  C,  coccyx;  G,  glu- 
teus maximus;  P,  perineal  body;  U,  urethra;  V,  vagina;  G,  vulvo- 
vaginal gland;  1,  clitoris;  2,  its  suspensory  ligament;  3,  crura  clito- 
ridis; 4,  erector  clitoridis;  5,  bulbo-cavernosus;  7,  transversus  perinaei; 
8,  sphincter  ani;  9  and  10,  levator  ani;  11,  coccygeus;  12,  obturator 
externus. 


Accelerator  ubism  or  ejaculatob  beminis  (m.  bidbo- 

cavernosus)  arises  from  central  tendon  of  perineum  and  from 
mediaii  raphe  in  front.     It  spreads  out  and   is   inserted   from 

behind  forward  to  anterior  surface  of  triangular  ligament,  bull) 
and  adjacent  part  of  corpus  spongiosum,  to  join  fibers  of 
opposite  side,  and  to  sides  of  corpora  cavernosa  ;  anterior  to 
erector  penis  and    in    fibrOUS  expansion   over  dorsal   Mood    vessels 

of  penis. 

It  accelerates  the  How  of  urine  and  semen  and  contributes 

to  erection  of  the  penis.     Nerve,  perineal. 


406  HUMAN    ANATOMY. 

Vaginal  constrictor  or  sphincter  vagina  (to.  bulho- 
cavemosus) ,  analogous  to  foregoing  muscle,  surrounds  the  orifice 
of  vagina.  It  arises  from  the  centraL^endon  and  passes  forward 
on  either  side  of  vagina  to  be  inserted  into  the  corpora  caver- 
nosa and  body  of  clitoris.  It  compresses  the  dorsal  vein  of  the 
clitoris. 

Transversus  perin^ei  (superficialis)  arises  from  inner 
part  of  ramus  of  ischium,  and  is  inserted  into  perineal  center 
in  male,  into  the  side  of  sphincter  vaginae  in  the  female.  It 
steadies  the  perineal  center.     Nerve,  perineal. 

Compressor  urethrje  (to.  constrictor  uretlirce)  arises 
from  the  rami  of  pubis  and  ischium,  passes  inward  and  with 
its  fellow  of  the  other  side,  unites  above  and  below  the  urethra, 
surrounding  it  from  the  bulbous  portion  to  the  prostate  gland 
in  the  male.     In  the  female  it  is  inserted  into  the  vaginal  walls. 

External  sphincter  ani  (to.  sphincter  ani  externus) 
muscle  arises  from  the  apex  of  the  coccyx  and  the  superficial 
fascia,  and  is  inserted  into  the  perineal  center,  blending  with 
the  levator  ani,  accelerator  urinae  and  transversus  perinaei.  It 
closes  the  anus.     Nerve,  fourth  sacral. 

Internal  sphincter  ani  (to.  sphincter  ani  internus)  is 
an  aggregation  of  circular  fibers  of  the  intestine,  forming  a 
muscular  ring  one  inch  in  breadth,  surrounding  the  lower  por- 
tion of  the  rectum. 

The  external  sphincter  ani,  the  two  bulbocavernosi  and  the 
two  transversus  perinsei  unite  one-half  inch  in  front  of  the  anus 
in  the  median  line  in  the  so-called  central  tendon  of  the  per- 
ineum. 

Anal  elevator  (levator  ani)  arises  in  front  from  body 
and  ramus  of  pubis  and  symphysis,  posteriorly  from  spine  of 
ischium,  and  on  either  side  from  angle  -of  arcus  tendinew  (white 
line).  It  is  inserted  by  posterior  fibers  into  coccyx,  and  ante- 
rior fibers  into  the  muscle  of  opposite  side  in  a  median  raphe 
extending  from  coccyx  to  anus ;  middle  fibers  into  rectum,  join- 
ing with  sphincter;  anterior  to  prostate,  blending  with  external 
sphincter  and  transverse  fascia.  In  the  female  it  is  inserted 
into  the  vagina  instead  of  the  prostate. 

It  helps  with  its  fellow  to  form  the  floor  of  the  pelvis,  and 
supports  the  vagina,  rectum  and  pelvic  viscera.  Nerves,  infe- 
rior hemorrhoidal  and  fourth  sacral. 

Cocctgeus  muscle  (coccygei) ,  from  the  spine  of  the 
ischium  and  lesser  sacrosciatic  ligament,  and  is  inserted  into 
the  margin  of  coccyx  and  side  of  lower  two  segments  of  sacrum. 


SURGICAL    ANATOMY.  407 

It  raises  the  coccyx  and  forms  the  posterior  part  of  the  pelvic 
floor.    Nerve,  anterior  division  of  the  fourth  and  fifth  sacral. 
The  muscles  of  the  female  perineum  are : — 

Superficial   Set. 

Sphincter  vagina',  or  bulbocavernosus; 

Erector  clitoridis ; 

Transversus  perinaei  superficial  ; 

Sphincter  ani ; 

Levator  ani : 

Coccygeus. 

Deep   Set. 

Transversus  perinaei  (profundus)  ; 

( SonstrictoT  vagina? ; 

Compressor  urethra1. 

The  structures  beneath  the  deep  layer  of  the  superficial 
fascia  are : — 

Erector  penis  muscle ; 

Accelerator  urinae  muscle ; 

Transversus  perinaei  muscle  and  arteries; 

Superficial  perineal  vessels. 

The  structures  between  the  two  layers  of  the  deep  perineal 
fascia  are : — 

( 'ompressor  urethra?  muscle; 

Membranous  urethra; 

Subpubic  ligament ; 

Dorsal  vein  of  penis; 

Pudic  vessels  and  nerves; 

Venous  plexus; 

Cowper's  glands  and  ducts; 

Arteries  and  nerves  of  bulb. 

ANATOMY     OF     LATERAL     LITHOTOMY. 

The  incision  is  made  through  a  triangular  interval  formed 
by  the  transversus  perinaei,  accelerator  urinae  and  erector  penie 
muscles,  and  divides  the  following  structures  in  the  order 
named : — 

Skin  and   superficial    fascia  : 

Inferior  hemorrhoidal  vessels  and  nerves; 

Accelerator  urinae  muscle ; 

Superficial  perineal  vessels  and  nerve  (sometimes); 


408  HUMAN    ANATOMY. 

Transversus  perinsei  artery  and  muscle; 
Deep  perineal  fascia; 
Anterior  part  of  levator  ani; 

Part  of  compressor  urethras  and  accelerator  urinse  muscles; 
Membranous  and  prostatic  portions  of  urethra; 
Left  lobe  of  prostate  gland. 
The  structures  to  be  avoided  are : — 
In  median  line,  rectum  and  bulb  of  corpus  spongiosum ; 
Externally,  internal  pudic  artery; 
Forward,  artery  of  the  bulb ; 

Backward,  posterior  part  of  prostatic  gland  and  neck  of 
the  bladder. 


DENTAL  ANATOMY. 


Embkyologically  the  oral  cavity  is  formed  by  the  first 
visceral  and  the  frontonasal  process.  The  first  arch  distad 
branches  dichotomously.  The  superior  arm  is  the  maxillary 
process,  the  inferior  arm  the  mandibular  process.  The  latter 
joins  with  its  fellow  of  the  opposite  side  in  the  midline  {sym- 
physis nuutdibularis)  to  form  the  lower  jaw.    Between  the  right 


Fig.  146. 

Maxillary  and  mandibular  process  of  first  visceral  arch  and 
frontonasal  process,  a,  frontonasal  process;  b,  superior  arm  (maxil- 
lary process)  of  first  arch;  C,  inferior  arm  (mandibular  process)  of 
first   arch;   <l,    primitive  oral   cavity. 


and  left  maxillary  processes  is  interpolated  the  frontonasal 
process.  This  marks  a  place  of  weakness,  pathologically  indi- 
cated by  congenital  clefi  palate  and  harelip. 

The  bony  framework  of  the  adult  oral  cavity  consists  of 
the  hard  palate  above  and  the  mandible  (Fig.  lfs)  and  hyoid 
(Fig.  35)  bones  below.  The  bones  entering  into  the  formation 
of  the  hard  palate,  from  before  backward,  are:  (1)  two  pre- 
maxillaries  (distinguishable  only  in  very  young  specimens).  (2) 
two  mamillaries,  and  (3)  two  palate  bones.  The  hard  palate 
presents  four  sutures:  (1)  median,  (2)  premaxillary-maxillarj 
(poorly  marked  in  Hie  adult),  (3)  maxillary-palatine,  and  (  I) 
palatine-sphenoid.  The  foramina  of  the  hard  palate  are:  (1) 
anterior  palatine,  at   the  point  where  the  preinaxillarY-niaxillarv 

(409) 


410 


HUMAN    ANATOMY. 


suture  crosses  the  median,  subdivided  into  four  openings,  (2) 
two  posterior  palatine,  and  (3)  twg.  accessory.  These  last  four 
foramina  transmit  the  posterior  descending  palatine  nerves  and 
vessels. 

The  alveolar  process  for  the  implantation  of  the  teeth  is  a 
ridge  of  bone  superimposed  peripherally,  in  the  upper  jaw,  upon 
the  premaxillary  and  maxillary  bones.  When  fully  functioning 
it  is  not  demarcated  from  these  bones,  but  before  the  teeth  come 
and  after  they  go  it  does  not  exist.  Its  body  is  spongy.  Its  cor- 
tex is  dense,  and  surrounding  each  tooth  root-socket  it  is  some- 
what condensed  (lamina  dura,  of  some  significance  radiographic- 
ally  for  the  prognosis  of  pyorrhea  alveolaris).     In  cross-section 


Fig.  147. 


Sutures   of   the   hard    palate,    a,    premaxillary    bone; 
maxillary  bone;  c,  palatine  bone. 


it  is  somewhat  U-shaped.  It  has  two  free  surfaces,  the  internal 
and  external  alveolar  plates.  Of  these  the  external  is  much  the 
thinner,  which  fact  is  taken  advantage  of  in  extraction. 

The  mandible  (Fig.  148)  exhibits  an  alveolar  process  essen- 
tially similar  to  that  of  the  maxillary.  In  cross-section  the 
mandible  is  U-shaped.  The  cortex  is  dense,  the  interior  cancel- 
lated. Within  its  body  runs  the  inferior  dental  nerve  and  blood- 
vessels inclosed  in  a  cribriform  tube  in  close  proximity  to  the 
roots  of  the  teeth.  In  most  cases  the  mental  canal  points  for- 
ward into  the  body  of  the  bone,  and  hence  it  is  a  recurrent  canal. 
There  are  two  foramina  in  the  niandible:  (1)  inferior  dental, 
situated  in  the  midvertical  axis  of  the  ramus  at  the  intersection 
of  a  line  continuous  with  the  free  edge  of  the  alveolar  process; 
(2)  mental,  situated  about  in  the  midhorizontal  line  of  the  body 
at  the  intersection  of  a  vertical  line  dropped  from  the  second 


DENTAL    ANATOMY. 


411 


premolar  or  between  the  first  and  second  premolars.  The  men- 
tal foramen  marks  one  of  the  favorite  lines  of  fracture  of  the 
mandible. 

Over  this  bony  scaffolding  the  soft  tissues  of  the  mouth  are 
molded.  The  hard  palate  is  covered  by  a  mucoperiostenni.  Its 
pitted  surface  is  due  to  many  small  mucous  glands  which  it 
shelters.  The  gums  covering  the  alveolar  processes  are  also  of  a 
mucoperiosteal  nature.  Normally  between  the  teeth  is  a  little 
cushion  of  gum-tissne.  serving  to  keep  out  food  debris.  Around 
each  tooth  the  gum  is  attached  at  the  neck  (enamel-cementum 


Four  mandibles  ranging  from  birth  to  eighteen  months.  A,  at 
birth:  li.  at  three  months;  C,  at  six  months;  /),  at  eighteen  months. 
•  ■Internal    Anatomy   of   the    Face,"    M.    11.    Cryer,    M.D.,    D.D.S.) 


junction),  but  a  little  free  edge  exists  leaving  around  each  toot!) 
;i  gingival  trough. 

The  Boft  tissues  over  the  anterior  part  of  the  hard  palate 
and  the  palatine  side  of  the  alveolar  ridge  is  raised  into  a  num- 
ber of  transverse  ridges  (rugae),  and,  in  the  midline,  an  ineisal 
pad. 

The  SOfl  palate  i-  ;i  backward  continuation  of  the  soft  tis- 
sues covering  the  hard  palate,  inclosing  in  their  substance 
muscle  fibers.  The  anterior  pillars  of  the  fauces  arbitrarily 
mark  the  posterior  limit  of  the  oral  cavity.  In  their  substance 
run  the  palatoglossus  muscles. 

Laterally  and   anteriorly  the  cheeks  and   li|is   form   the  walls 

of  the  oral  cavity.    The  -Jit  between  the  external  alveolar  plate 
and   teeth  on  the  one  side,  and  the  cheeks  and    lips  on   the  other 

is  known  a-  the  preoral  cavity  or  vestibule.    The  frenum  l<il>ii  is 


412 


HUMAN    ANATOMY. 


a  delicate  fold  of  tissue  in  the  midline  between  the  gum  of  the 
external  alveolar  plate  and  the  upper  lip.  In  artificial  dentures 
room  has  to,  be  provided  for  its  free  movement. 

The  body  of  the  cheeks  and  lips  is  composed  of  the  muscles 
of  expression  (Fig.  149).  Internally  they  are  covered  by 
mucosa,  externally  by  the  skin. 


fig.  149. 

Muscles  of  expression.  Muscles  of  the  right  side  of  the  head 
and  neck.  1,  frontalis:  2,  superior  auricular;  3,  posterior  auricular; 
4,  orbicularis  palpebarum;  5,  pyramidalis  nasi;  6,  compressor  naris; 
7,  levator  labii  superioris,  alaeque  nasi;  8,  levator  labii  superioris;  9, 
zygomaticus  major;  10,  orbicularis  oris;  11,  depressor  labii  inferioris; 
12,  depressor  anguli  oris;  13,  anterior  belly  of  digestric;  14,  mylo- 
hyoid; 15,  hyoglossus;  16,  stylohyoid;  17,  posterior  belly  of  digastric; 
18,  masseter;  19,  sternohyoid;  20,  anterior  belly  of  omohyoid;  21, 
thyrohyoid;  22,  23,  lower  and  middle  constrictors  of  the  pharynx; 
24,  sternomastoid ;  25,  26,  splenius;  27,  levator  scapulae;  28,  anterior 
scalenus;  29,  posterior  belly  of  omohyoid;  30,  middle  and  posterior 
scalenus;  31,  trapezius.  ("Applied  Anatomy  and  Oral  Surgery," 
Robert  H.  Ivy.) 


The  anterior  orifice  of  the  oral  cavity  (rima  oris)  is  a  trans- 
verse slit  bounded  by  the  projecting  lips.  The  orbicularis  oris 
(page  132)  has  no  separate  existence.  The  sphincter  action  of 
the  lips  is  accomplished  by  a  complicated  interlacing  of  the 
muscle  fibers  from  buccinator,  depressor  labii  inferioris,  depres- 
sor anguli  oris,  zygomaticus  and  risorius.  The  buccinator  forms 
the  muscular  body  of  the  cheek.  Its  attachment  to  the  maxilla 
has  to  be  considered  in  outlining  upper  artificial  dentures. 


DENTAL    ANATOMY. 


413 


The  masseter,  temporal,  external  and  internal  pterygoids 
all  innervated  by  the  fifth  nerve,  are  the  "muscles  of  mastica- 
tion" (pages  132  and  133).  Between  the  right  and  left  halves 
of  the  body  of  the  mandible  is  the  muscular  floor  of  the  mouth — 
digastric,  geniohyoid  and  mylohyoid  (.page  134). 

The  floor  of  the  oral  cavity  presents  the  tongue,  with  its 
frenum;  on  each  side  of  this  an  elevation  indicating  the  posi- 
tion of  the  sublingual  glands,  and  anteriorly  to  the  frenum,  a 
papilla  for  the  orifices  of  the  sublingual  and  submaxillary  ducts. 
For  the  description  of  the  tongue  see  pages  135  and  388. 

For  the  salivary  glands  see  pages  229-230. 


Tooth    development.     </,    dental    ledge   or    lamina;    b,    tooth    germs   of 
deciduous  teeth. 


For  the  temporomandibular  articulation  see  pages  105 
and  106. 

The  cranial   nerves  of  direct  interest  for  the  dentist  are 

fifth  nerve,  seventh  nerve,  ninth  nerve  and  twelfth  nerve.     (See 

pages  311-316  and  Figs.   116  and  117).     Especially  fifth  and 

seventh   nerves  must  be   thoroughly  mastered.      (Chart   facing 

122.) 

The  external  carotid  artery  (pages  180-185  and  Figs.  79 
and  81)  is  the  most  important  artery  for  the  dentist.  See  also 
table  on  pages  200-204.  For  the  venous  system  of  special  in- 
terest to  the  dentist  see  pages  210-213. 

The  nasal  cavity  and  its  accessory  sinuses  not  infrequently 

have  relations  of  dental  interest  (Figs.  125,  126  and   ]~yt  and 

355  and   356).     The  relations  of  the  roots  of  the  upper 

second    premolar,    first    and    second    molars    to    the    Hour   of   the 

maxillary  -inns    (antrum  of  Highmore)    is  very  intimate  and 


414 


HUMAN   ANATOMY. 


important.    The  roots  of  the  two  last-named  teeth  always  indent 
the  floor  of  this  sinus. 

The  mandible  is  raised  by  the  masseter,  temporal,  external 
and  internal  pterygoids;  depressed  by  the  anterior  belly  of  the 
digastric  and  geniohyoid  when  the  hyoid  bone  is  fixed ;  protruded 
by  external  and  internal  pterygoids  as  well  as  slightly  by  the 


Dental  lamina 


Epidermis 


Tooth   development.      ("A   Laboratory   Manual   and   Textbook 
of  Embryology."  Prentiss.) 


superior  portion  of  the  masseter;  retracted  by  the  posterior 
fibers  of  the  temporal;  and  rotated  by  the  fixation  of  one  exter- 
nal pterygoid  with  synchronous  contraction  of  the  other  (the 
internal  pterygoid  assists  in  rotation). 

The  teeth  are  inserted  by  a  gomphosis  joint  in  the  alveolar 
processes  of  the  lower  and  upper  jaws.  In  man  tbere  is  a 
deciduous  and  a  permanent  set.  There  are  twenty  deciduous 
teeth;  five  in  each  quarter  of  the  jaw  apparatus:  2  incisors,  1 
canine  and  2  molars  (Fig.  86,  page  226). 


DENTAL   ANATOMY.  415 

There  are  thirty-two  permanent  teeth;  eight  in  each  quar- 
ter of  the  jaw  apparatus:    2  incisors,  1  canine,  2  premolars    3 

molars  (Fig.  87,  page  227). 

The  human  tooth  presents  a  crown  and  a  root.  The  crown 
is  outside  of  the  gum,  and  is  covered  with  enamel.  The  root  is 
for  the  insertion  of  the  tooth,  and  is  covered  with  cementum  At 
the  junction  of  the  crown  and  root  is  a  constriction,  the  neck  or 
cervix.  The  body  of  the  tooth  is  formed  of  dentine.  Within 
the  dentine  is  the  pulp  which  in  the  crown  is  contained  in  a 
relatively  large  chamber,  sending  out  cornua  roughly  corre- 
sponding to  the  cusps  of  the  tooth;  in  the  root  the  pulp  is  re- 
stricted to  the  narrow  canal  terminating  outwardly  at  the  root 
apex  through  one  or  several  foramina. 

In  the  seventh  fetal  week  the  oral  epithelium  thickens  along 
a  line   roughly  corresponding  to   the  future   dental  arch    pro" 
trading  into  the  underlying  jaw-mesenchvme.     In  each  jaw  at 
ten  points  in  this  dental  ledge,  on  its  deep  free  edge,  localized 
thickenings  become  noticeable.     These  are  the  'first  signs  of  the 
tooth-germs  of  the  deciduous  teeth.     Each  of  these  knobs  be- 
comes mvagmated,  the  cavity  filled  with  vascular  mesenchymal 
tissue,  the  dental  papilla.     By  progressive  development  the  part 
derived  from  the  oral  epithelium  becomes  the  enamel-organ  of 
the  future  tooth.     From  the  enamel-organ  are  formed  enamel 
and  Nasmyth's  membrane;  from  the  dental  papilla,  dentine  and 
pulp.      J  he  dental  ledge  connecting  the  tooth-germs  with  the 
oral  epithelium  becomes  fenestrated  and  eventually  disappears. 
_    Linguad  and  distad  to  each  of  the  deciduous  tooth-germs 
arises,  from  the  same  dental  ledge,  the  enamel-organ  of  the  cor- 
responding permanent  tooth.     The  three  permanent  molars  are 
derived  from  a  free  prolongation  of  the  dental  band,  extending 
distad  to  the  second  deciduous  molar. 

Ei  uption  of  Deciduous  Teeth. 

Mandibular  firai   incisors   0  to    8  months. 

Maxillary   first   and  second  incisors    ....      8  "     10 
Mandibular  second  incisors                      ) 

-Maxillary  and  mandibular  first  molars/   12  "    14 

canines    ....    IS  "    20  " 

second  molars.    28  "    32  " 


416  HUMAN    ANATOMY. 

Eruption  of  Permanent  Teeth. 

Maxillary  and  mandibular  first  molars   6  years. 

"             "              "              "     incisors 7  " 

"              "            second  incisors .......  8  " 

"                             "            first  premolars   9  " 

"            second  premolars   ...  10  " 

"            canines   11  " 

"            second  molars 12  " 

"  "  "  third  molars    17-25 


HISTOGENESIS    OF    THE    DENTAL    TISSUES. 

Enamel. — A  delicate  cuticular  zone  appears  at  the  inner 
end  of  the  amelohlast.  This*,  with  its  fellows  of  adjoining  cells, 
becomes  differentiated  into  rod-like  segments  (enamel-processes 
or  processes  of  Tomes)  :  these  develop  into  the  enamel  prisms 
and  interprismatic  substance.  The  enamel-processes  gradually 
become  calcified  by  the  deposition  of  granules  and  spherules, 
first  appearing  in  the  axis  of  the  prism  and  later  extending  to 
its  periphery.  These  spherules  are,  in  chemical  nature,  calco- 
globulin;  and  morphologically,  are  known  as  calcospherites. 
The  same  ameloblasts  suffice  for  the  deposition  of  the  entire 
mass  of  enamel.  This  is  formed  from  within  outward,  i.e.,  in 
the  reversed  direction  followed  by  the  growth  of  dentin.  It  is 
as  yet  undecided  whether  enamel  is  a  secretion  or  a  conversion 
of  the  ameloblasts,  but  the  balance  of  opinion  would  seem  to  be 
in  favor  of  the  latter  view. 

Dentin. — In  the  formation  of  dentin  the  odontoblasts  play 
much  the  same  role  that  is  played  by  the  osteoblasts  in  produc- 
ing the  matrix  of  bone.  A  thin  homogeneous  layer — membrana 
prceformativa — overlying  the  odontoblasts  is  the  earliest  trace. 
This,  however,  is  only  part  of  the  general  dentinal  ground-sub- 
stance— matrix — which  for  a  time  is  without  fibrous  structure 
and  uncalcified. 

Hopewell- Smith  does  not  agree  with  the  above  description, 
which  is  the  one  generally  accepted.  According  to  him  the 
classical  "odontoblasts"  have  nothing  to  do  with  the  formation 
of  dentin-matrix,  which  is  formed  by  a  calcification  proceeding 
from  certain  cells  of  the  pulp.  The  walls  and  contents  of  the 
tubuli  are  manufactured  probably  by  the  classical  "odonto- 
blasts." 

Cementum. — This  is  a  product  of  the  osteoblasts  (cemen- 
toblasts)  of  the  periodontal  ( alveolo-dental )  ligament.  The 
process  is  almost  identical  with  the  development  of  subperiosteal 
bone.     Cementum  is  distinguished  by  the  unusual  number  of 


DENTAL    ANATOMY. 


417 


transversely  placed  bundles  of  fibrillar — or  Sharpey's  fibers. 
Many  of  these  are  imperfectly  calcified.  The  cementum  appears 
first  in  the  vicinity  of  the  neck  of  the  tooth  and  advances 
towards  the  apex  of  the  root  as  the  radicular  dentin  is  laved 
down. 

The  knowledge  of  root-fonnation  is  important.  The  extent 
of  root-growth  at  various  ages  is  graphically  illustrated  by 
Fig.  152. 

The  dental  tissues  are:  (1)  Xasmytlvs  membrane,  (?) 
enamel,  (3)  dentine,  (4)  cementum,  (5)  pulp.  Nasmyth's 
membrane  is  a  pellicle  9  to  18u.  thick)  covering  the  enamel,  long 
persisting,  of  high  organic  content,  resistant  to  the  action  of 
acids.  It  is  two-layered:  (1)  outer,  of  cornified  remnants  of 
enamel-organ;    (2)    inner,   structureless,   consisting  of  the  last 


V*°«f. 


2.SII  week  embryo 


FKi.    152. 
Root   growth. 


formed,  imperfectly  calcified  portion  of  the  enamel-prisms. 
The  enamel  is  the  hardest  tissue  of  the  human  body  (containing 
!»^  per  cent,  of  inorganic  salts).  It  consists  of  prisms  (.'5.4-4.5^ 
in  diaMeter)  running  approximately  at  right  angles  to  the  ex- 
ternal surface  of  the  tooth,  in  a  slightly  spiral  course  to  the 
dentine.  Between  these  prisms  is  a  cementing  substance.  In 
the  outer  portions  of  the  enamel,  intercalated  or  accessory 
prisms  have  been  described.  The  margin  of  each  enamel-rod  is 
straight  and  smooth,  but  may  optically  appear  varicose,  due  to 
the  beaded  nature  of  its  more  highly  calcified  central  portion. 
The  brown  stria-  of  Retzius  are  pigment  zones  running  in  the 
general  direction,  of  the  contour  of  the  tooth.  The  prism- 
stripes  of  Schreger  are  alternate  dark  and  light  bands  at  right 
;mgle-  to  the  striae  of  Retzius  in  the  enamel,  cut  in  axial  longi- 
tudinal pection  and  examined  hv  reflected  light. 

The  dentine  contains  about  72  per  cent,  of  inorganic  salts. 
It-  histologic  character  La  principaly  due  to  the  dentinal  tubuli 


87 


418  HUMAN   ANATOMY. 

(1.3-2/u-  in  diameter),  which,  running  sinuously  from  the  pulp 
to  the  enamel,  contain  the  dentinal  fibers,  the  odontoblastic 
processes.  These  tubuli  branch  and  anastomose,  some  of  them 
ending  in  the  enamel  in  the  form  of  enamel-spindles.  The 
sheath  of  Newman  is 'a  delicate  membranous  wall  of  the  den- 
tinal tubule.  The  dentinal  substance  between  the  tubuli  is 
similar  to  the  matrix  of  bone.  Imperfections  in  the  calcifica- 
tion of  the  dentine  are  indicated  by  the  interglobular  spaces  and 
contour  lines  of  Owen  in  the  coronal  portion,  and  the  granular 
layer  of  Tomes  at  the  dentine-cementum  junction  in  the  root 
portion.  Schreger's  lines  in  the  dentine  "are  merely  markings, 
which,  running  parallel  to  the  external  edge  of  dentine,  are  pro- 
duced by  the  coincidence  of  primary  curvatures  of  the  tubules." 

The  cementum  is  usually  described  as  being  composed  of 
relatively  amorphous  concentric  lamellae  with  lacunae.  There  is, 
however,  good  authority  (Hopewell-Smith)  for  considering  the 
lacunae  indicative  of  some  pathological  process.  The  cementum 
increases  in  thickness  from  the  gum-margin  to  the  root-apex 
and  also"  with  age.  The  relation  between  the  enamel  and 
cementum  is  variable ;  inmost  cases  these  two  tissues  just  touch 
each  other-. 

The  pulp  shows  connective  tissue  of  an  embryonal  type. 
There  are  very  few  or  no  elastic  fibers  in  it.  Its  nerve-  and 
blood-supply  is  abundant.  Lymphatics  are  generally  denied, 
but  recent  work  indicates  their  presence.  The  peripheral  cells 
are  differentiated  into  a  more  or  less  stratified  columnar  ele- 
ments, the  odontoblasts,  which  send  their  processes  into  the 
dentinal  tubuli.  The  nerves  accompany  the  blood-vessels  and 
from  a  peripheral  plexus  beneath  the  odontoblasts,  sending 
fibrillae  between  thes%  cells.  Any  further  extension  of  these 
nerves,  e.g.,  into  dentine,  has  as  yet  not  been  proved. 

The  periodontal  ligament  is  a  collection  of  fibrous  tissue 
stretching  from  the  dentine  to  the  lamina  dura  of  the  alveolar 
socket.  The  arrangement  of  the  fibers  is  adjusted  in  general  to 
meet  the  strain  of  occlusion.  This  ligament  is  normally,  in 
youth,  relatively  thick  in  diameter,  decreasing  with  age  and 
pathological  conditions.  It  contains  cell-nests  or  "rests,"  rem- 
nants of  the  epithelial  sheath  of  Hertwig,  once  described  as 
glands. 

The  deciduous  teeth  (Fig.  86,  page  226)  are  smaller  than, 
and  show  a  more  marked  cevical  construction  than,  the  per- 
manent teeth.  Also  the  roots  of  the  milk-molars  exhibit  a  more 
marked  flaring.  The  first  and  second  deciduous  incisors  re- 
semble in  close  detail  the  corresponding  permanent  teeth.     The 


DENTAL    ANATOMY.  419 

second  milk-molar  bears  a  greai  resemblance  to  the  first  per- 
manent molar.  The  occlusal  surface  of  the  maxillary  (upper) 
first  deciduous  molar  is  irregularly  quadrangular  in  outline,  and 
presents  three  cusps ;  two  buccally  and  one  lingriallv.  It  has  three 
roots.  The  occlusal  surface  of  the  mandibular  (lower)  first 
deciduous  molar  is  quadritubercular  (two  buccal  and  two  lingual 
cusps).     It  has  two  roots,  one  mesial,  one  distal. 

The  Permanent  Teeth. 

Maxillary  first  (central)  incisor,  chisel-shaped;  labial  sur- 
face somewhat  convex;  lingual,  concave;  incisal  edge  curves  over 
into  distal  surface;  incisal-mesial  angle  sharp;  root  conical. 
Implanted  in  premaxillary  bone  (  Fig.  ST,  page  227). 

Maxillary  second  (lateral)  incisor  closely  resembles  upper 
first  incisor.  It  is  about  two-thirds  the  size  of  this  latter  tooth. 
Implanted  in  premaxillary  bone. 

Maxillary  canine;  convex  labial  surface  presents  a  cutting 
edge  with  a  mesial  and  a  distal  slant;  latter  the  longer;  lingual 
surface  almost  flat  or  slightly  convex;  near  gingival  border  is  a 
small  protuberance  or  cingulum;  root  longest  in  human  mouth, 
irregularly  conical  in  shape,  tapering  from  neck  to  apex. 

Maxillary  first  premolar;  bicuspid  crown  (one  lingual,  one 
buccal  cusp);  latter  the  larger;  buccal  surface  presents  a  free 
mar-in  with  mesial  and  distal  slant,  former  generally  the 
longer;  root  generally  flattened  and  grooved  on  its  mesial  and 
distal  sides,  or  separated  into  a  buccal  and  a  lingual  root 
(Pig.  153). 

Maxillary  second  premolar;  closely  /esembles  above  tooth; 
slightly  smaller;  its  crown  is  lower;  distal  slant  on  free  margin 
of  its  buccal  surface  slightly  the  longer;  root  slightly  the  longer, 
rarely  divided,  much  flattened  mesiodistally. 

Maxillary  first  molar;  occlusal  surface  irregular  rhombic  in 
outline  with  four  cusps  (two  buccal,  two  lingual)  ;  mesiobuccal 
cusp  largest;  distolingual  cusp  distinctly  marked  oil'  from  the 
other  cusps  by  a  deep  groove ;  three  roots  (1)  mesial  or  mesio- 
buccal, (2)  distal  or  distobuccal,  (3)  lingual;  (3)  largest, 
conical  in  form,  circular  in  cross-section;  mesial  root  larger  than 
distal,  oval  in  cross-section,  with  buccolingual  axis  the  longer; 
distal  root  also  has  the  same  eross-section   (Fig.  154). 

Maxillary  second  molar;  smaller  than  above  tooth;  other- 
wise   greai     similarity;    distolingual     cusp     noticeably     reduced; 

three  roots,  closely  resembling  those  of  above  tooth. 


420 


HUMAN    ANATOMY. 


Maxillary  third  molar;  same  structural  form  as  the  two 
above  teeth,  but  many  variations;  cusps  more  poorly  marked; 
distolingual   cusp   often   absent;   smallest  tooth   of  the  molar 


Fig.  153. 

Occlusal    surfaces   of    teeth.      ("Descriptive    Anatomy    of    the    Human 
Teeth,"   G.   V.  Black,  M.D.,  D.D.8.,  8c. D.) 

series ;  roots  may  be  the  typical  three,  or  these  may  be  fused  more 
or  less  completely  into  one,  or  there  may  be  supernumerary  roots. 
Mandibular  (lower)  first  and  second  incisors;  very  similar 
to  maxillary  second  incisor,  but  more  slender;  incisal  edge  of 
first  incisor  is  almost  at  a  ri°;ht  ansrle  to  the  lono-  axis  of  the 


DENTAL    ANATOMY. 


421 


tooth:  its  mesio-  and  disto-incisal  angles  are  sharp;  second  in- 
cisor differs  from  the  first  by  possessing  an  incisal  t'ilge  curving 
at  the  distal  angle  and  sharp  at  the  mesial  :  roots,  slender,  Hat- 
tended  mesiodistally,  oval  in  cross-section,  with  long-  axis  labio- 
lingually. 

Mandibular  canine;  markedly  similar  to  maxillary  canine, 
slightly  smaller,  crown  a  little  longer;  root  shorter,  somewhat 
flattened  mesiodistally,  nearly  straight. 

Mandibular  first  premolar:  emallesi  of  the  premolars;  buc- 
cal and  lingual  cusps,  latter  almost  absent,  neck  much  con- 
stricted. 


Pig.  154. 

Cross    sections    through    roots    of    teeth    in    *iln.      Actual    size.     ("Descriptive 
Anatomy   of   the   Human   Teeth,"    G.    V.   Black,    M.D.,    D.D.8.,    8c.D.) 


.Mandibular  second  premolar;  very  similar  to  above  tooth: 
slightly  longer;  lingual  cusp  more  marked;  root,  longer,  larger, 
generally  straight. 

Mandibular  first  molar;  next  to  maxillary  first  molar  the 
largest;  outline  of  occlusal  surface  trapezoidal;  buccal  margin 
the  longest;  five-cueped  (three  buccally,  two  lingually) ;  mesio- 
buccal  cusp  largest  :  two  root-,  one  mesial,  one  distal ;  former  the 
larger,  oval  in  cross-section,  contains  two  root  canals:  distal 
root,  oval  in  cross-section,  one  root  canal. 

Mandibular  second  molar ;  strikingly  differed  from  the  lirsi 
in  absence  of  distal  (distobuccal)  cusp:  in  all  other  respects 
greai  similarity. 

Mandibular  third   inohir;  two  typical   forms  :     (1)    four-cus- 

j"'d.  similar  to  mandibular  second   molar   (the  more  common 


422  HUMAN    ANATOMY. 

form)  ;  (2)  five-cusped,  similar  to  mandibular  first  molar. 
From  these  types  great  variation  in  size  and  form.  On  the 
whole  smaller  than  the  two  teeth  immediately  mesial  to  it; 
typically  two  roots,  relatively  smaller  than  other  molar  roots, 
single  root  also  common;  three  roots  not  infrequent;  however, 
always  three  root-canals,  two  mesial  and  one  distal. 

The  anatomy  of  the  teeth,  apart  from  their  occlusal  topog- 
raphy, may  be  epitomized  as  follows :  Incisors,  canines  and  pre- 
molars ;  all  one  root  with  exception  of  maxillary  first  premolar, 
which  has  two.  Maxillary  molars;  three  roots.  Mandibular 
molars;  two  roots.  Incisors  have  a  straight  cutting  edge; 
canines  and  premolars  have  a  mesial  and  a  distal  slant;  mesial 
slant  the  shorter,  exce])t  that  the  mesial  slant  of  first  maxillary 
premolar  is  the  longer.  Mesiobuccal  angle,  acute.  Eoots  bend 
distally;  mesial  root  the  longer. 

Occlusion. — Maxillary  teeth  bite  to  the  outside  of  the 
mandibular  teeth ;  the  buccal  cusps  of  the  mandibular  premolars 
and  molars  fit  into  the  mesiodistal  groove  of  the  corresponding 
maxillary  teeth ;  maxillary  canine  locks  between  mandibular 
canine  and  first  premolar.  Every  tooth  in  the  human  denture 
opposes  two  teeth  of  the  occluding  set,  except  the  mandibular 
first  incisor  and  maxillary  third  molar. 

The  point,  or,  better,  the  surface,  of  proximate  contact  is 
that  area  on  the  mesial  and  distal  surface  of  a  tooth  which  ap- 
poses a  corresponding  surface  of  the  adjoining  tooth.  Eacli 
tooth  thereby  receives  mutual  support  from  two  adjoining  teeth, 
except  the  four  third  molars,  which  have  only  on  their  mesial 
sides  these  surfaces  of  proximate  contact. 


Distribution 


Termination  &  Function 


CRANIAL     NERVES. 


Sommering 


I.  Olfaotory. 


3.  Motor  ooull. 


4.  Pathetic? 

(trochleares). 


5.  Trifacial    (tri- 
gemini). 


6.  Abducentet. 

7.  Facial. 


8.  Auditory. 

9.  Glosso-pharyn 


10.  Pneumogastrio 
(vagus). 


Superficial  Origir 


Opposite  the  internal 
auditory  meatus  the 
sensory  root  enters  the 


beneath  and,  later, 
joins  a  branch  of  the 
ganglion. 


Pyramidal     body    and 


r  commis- 
;rior  white 

f  the  opti 


Optic  thala 
geniculate, 
quadrigen 


Aqueduct    of    Sylv 
floor    of    fourth    v 


Sensory  root,  from  1 
eral  tract  of  the  i 
dulla  oblongata. 


Posterior    part    of 


Gray  nucleus  in  floor  of 
fourth  ventricle. 


Byfilnmentsfrom  spinal     Acressory  portion  from 


\hout  si  iln/.i'ii  filaments 
from  the  space  between 
tiie  pyramidal  uud  oli- 
vary bodies. 


Gray    nucleus    in    floor 
of  fourth  ventricle. 


Sphenoidal  between  t' 


Sphenoidal  fissure. 


Internal    auditory 


Internal    auditory 


in  front  of  the  pneu- 
mogastric  anil  spinal 
accessory. 
Two  gangliform  en- 
largements in  jugular 
foramen— jugular  and 
petrosal. 

Jugular  foramen  in  a 
common  sheath,  with 
tin-  spinal  accessory. 


jugular 

She. Ull 

gastric. 


t  branch  to  the 


[Nasal. 

**  Infra  trochlear. 
r  ma.xillarv.  three  groups — 

io-mnx.  lossaj  Splu,no_pa].ltil]C| 
[  Posterior  dental. 


On  the  face  1  Nasal, 
(  Labial. 
Inferior  maxillary,  two  divii 

Anterior,  principally  moti 


Auric ulo- temporal  2 


.  Two  auricular. 

Communicating  branches, 
of  distribution. 


ranches  before  its  exit  are — 

(  Tympanic, 

(  i  'horda  tympani. 


Tempoi 


c  Temporal, 

i-facial }  Malar, 

(  Infraorbital. 
(  Buccal, 
Ccrvi co-facial    <  Suprurnax  diary, 
(  Inframaxillary. 


Tympanic  (Jacobson's 


Muscular, 

Tonsillar, 


In  jugular  fossa— Auricular. 

{Pharyngeal, 
Superior  laryngeal, 
ReciiiTcnt  laryngeal, 
Cervical  cardiac. 

(Thoracic  caTdiac, 
Antenorpulua.nary. 
Posterior  pulmonary. 
(Esophageal. 
In  abdomen — Gastric. 

Accessory  portion. 

Spinal  portion. 


Distribution 


Tuiht  rrrniip — nasal  septum. 

Middle  group — roof  of  nasal  fossa. 

Outer  group — superior  and  middle  tubinated  bones. 


Expands  to  form  the  inner  layer  of  the  retina  o(  the  eye. 


Superior — to  the  superior  r 
(  1st  branch — to  1: 

Inferior  <  2d  branch — to  i: 
(  8d   branch— to  t 


r  oblique  or  trochlcatis muscle. 


Entera  muscle  c 


Lachrymal  gland,  conjunctiva,  in  tinmen  t  of  upper  eyelid 
I'orrugator  supcrcillii,  oceipiio-froninlis,  nili-mm.  nt  of  forehead 
I'orrugator   supcrcillii,    orbicularis  [.dpchrar'un,    occlpuo-fromalis 
Mucous  membrane  of  no.-c.   HI  I  egiliiiuii  o|    wings-  and  ti].  Of  nose. 
*  'tliary  ganglion. 
Ciliary  iuusele  and  iris. 
Integument  of  eyelids  and 
conji      ' ' 


ncula  lachrymalis,  lachrymal  e 


"rUcularis  palpebrarum,  ■ 

Integument  of  temple  and  side  of  forehead. 

Joins  facial  nerve. 

Two  branches  to  spheno-palatine  ganglion. 

Anterior  branah  to  gums  anil  bucciintor  muscle  ;  posterior  branch  to  molar  and  second  bicuspid 

teeth,  antrum,  and  gumg. 
Incisor,  canine,  and  first  bicuspid  teeth  and  inferior  meatus 
Orbicularis  palpebrarum,  con  junem-ii  and  integument  of  lower 
Muscles  and  integument  of  inner  Bide  of  m 
Labial  glands,  muscles,  integument,  and  n 
To  the  muscles  of  mastication  the  brinchei 


,  branches  to  parotid  gland. 


dealing  with  submaxillar!  '.Miiglion  ami  hypoglossal  ni'i 
=i  nn'iiibianc  of  tongue,  mucous 
2  with  the  hypoglossal  n 


emhraiie  of  mouth,  gun 


Molar  and  bicuspid  teeth. 


r  belly  of  the  digastric  muscle. 


.  .Ties  of  tongue. 
Retrateus  uurmn.  oecipito-fron!:dis  (occipital  portion). 
Posterior  belly  of  digastric,  ril.iriso-m  to  glossopharyngeal  r 


n  the  submaxillary  gland.    Joins  sub 


i  sympathetic  or  earolida. 


Superficial  branches  to  skin  ami  muscles  of  face,  up  branches  levator  muscles  of  mouth. 

Buccinator  and  orbicularis  oris  muscles. 

Platysma,  muscles  of  chin  and  lip,  depressors  of  angle  of  mouth. 

Platysma.     One  branch  joins  tin.-  superficial  cervical  nerve. 

Cochlea. 

Vestibule  and  semicircular  canals. 


Trunk  of  internal  carotid  artery,  communicates  with  pncumogastiic  and  sympathetic. 
Mucous  membrane  of  pharynx. 
Stylo-pharyngeus  muscle. 
Tonsil,  soft  palate,  and  fauces. 

One  branch  to  mucous  membrane  surface  and  base  of  tongue  ;  one  branch  to  mucous 
and  papillre  of  sides  of  tongue. 


ith  auricular  branch  of  facial.     To  integument  of  Pinna. 
With  a  filament  I'mm  spinal  ace.  >sr,ry  \,,  pharyngeal  plexus  on  middle  constrictor. 
Mucous  membrane  of  interior  of  larynx  and  arytnioideus  muscle.      Exterior  laryngeal   i 
'"'  "  yroid  muscles,  branch  pharyngeal  plexus. 
■thyroid. 


Two 

ficial  card: 
To  deep  cardi 


sple: 


n  left. 


Anterior  pulmonary  plexUS. 

Posterior  pulmonary  plexus. 

Plexus  gulfe.  arouud  the  ccsophagus. 

Stomach,  communicating  with  solar,  splenic,  and  hepatic  plexuses. 

eating  branches  to  pharyngeal  and  superior  laryngeal  branches  of  the  pneuuio- 

id,  trapezius,  cervical  plexus,  occasionally  great  auricular  nerve. 


Omo-byoid  (both  bellies),  sternodiyoid,  sterno-thyroid. 

Thyro  hyoid  muscle. 

Styloglossus,  hyoglossus,  geuio-hyoid,  genio  hyogloesua. 

With  pm-uuiog's.-.trie,   sympathetic,   first  and  scpjji.l  cervical  and  gll-talory  I 


Termination  0  Functio 


Schneiderian  muco 

brane  of  the  nosi 

Nerve  of  special 


foramen. 
Nerve  of  special  i 


In    the     superior     obliqui 


(The  trifacial  is  the  large: 


■gesk 


In  muscles.     Nerve  of  i 


Nerve  of  special 


Nerve  of  motion. 

Nerve  of  facial  expression. 


Internal  ear. 
Nerve  of  special  si 

muscle. 
Nerve   of  special  s( 


In  muscles,  mucous  r 
brane,  vessels,  g 
(thyroid). 

Nerves  of  motion,  si 
tion,  and  sympathy. 


In  muscles. 
Nerve  of  tni 


INDEX. 


Abdomen. 

muscles    of.    1-13 

regions    of,    2'M 
Acervulus   cerebri,    315 
Acetabulum,   81 
Alveoli    of   lower   jaw,    36 

of   upper   jaw.    31 
Amphiarthrosis. 
Anastomoses.    174 
Anatomy,   descriptive,   1 

dental,    409 

general.    1 

of   hernia.    396 

of    lateral    lithotomy,    407 

of   teeth,    422 

surgical,    391 
Angle   of    jaw.    :'.7 
Anterior    perforated    space.    306 
Annulus    ovalis,    171 

of    subscapular    fossa.    65 
Antrum   of   Ilighmore.   29,   413 

relation    of   roots   of   teeth    to.    413 
Anus,    I'll 
Aorta,    17s,    193 
Appendicies    epiploic*,    244 
Appendix   auriculae,    170,    172 

ensiform,   '^ 

vermiformis,    243 
Aponeuroses.     129 

pharyng.  al,    230 
Apophysis,    4 
Aqueduct    of    Svlvius     (iter    e    tertio, 

etc.),    299 
Aqueductus   cochlea-,    is 

fallopii.    is.    ::us 

vestibule,    18 
Arachnoid,    of   brain.    L"'7 

of   spinal    cord,    ::::! 
Arbor   vita-.    290,    285 
Arch,   deep  palmar,   192 

plantar,   202 
Areola  of   mammae,  292 
Arm,   63 
Arnold's    ganglion.    352 

propria-   renales,    _•;* 
Arterial    anastomoses,    171 
in,    table    of.    202 
Arteries,    belicine,    280 

hepatic,    194,    249 

lingual, 

pharyngeal 

sublingual,    180,   isi 
Arteries  of   the   ankle-joint,    125 

auditory    canal.    36i,    376 

auricle,   376 

bom 

choroid.    363 

elbow    |oint,      123 

tcbian    tube,   .:7:i 
::7I 

hip-joint,    120 


Arteries  of  the  iris,  364 
kidney,    268 
knee-joint.     121 
labyrinth,    382 
larynx,    259 
lung,    it,:: 
mamma-,    292 
mambrana    tympani,   380 
nasal    fossa?,    356 
nose,    355 
oesophagus,   193 
ovaries,    284 
pancreas,    246 
penis,    280 
pharynx,    230 
retina,    36S 
shoulder-joint,    116 
spleen,   251 
stomach,    240 
suprarenal   capsules,   253 
testicle,    278 
thymus   gland,    25L' 
thyroid  gland,   252 
tympanum,    380 
uterus.   :!xi 
wrist-joint,    lis 
Artery,    anastomotica    magna,    191,    200 
aorta,    178,    193 
arteria   reeeptaculi,    is:, 
auricular,    posterior,    183 
axillary,    150 
basilar,    188 
brachial,    191 
carotid,    common.    17:i 

external,   180 

internal,    185 
carotid    (external I,    180 
(internal  I.    185 
cerebral,    anterior.    186 

middle,    anterior,    186 

posterior,    186 
choroid,    anterior,    186 
circumflex,    anterior.    189,    191 

posterior,    191 
communicating,   anterior,   186 

posterior,    186 
coronary,    178,    179 
dental,    inferior.    L84 
digital,    193,    202 
dorsalis,    hallucls,   201 

pedis,  201 
i -trie,   deep,  198 

superficial,   199 
I.    181 
lc,    194 
femoral,    L99 
gluteal,    198 

irrhoidal,    inferior,   197 

middle.    197 
,    195 

patlc,    194 
iliac,  circumflex,   deep,   198 


I  123) 


424 


INDEX. 


Artery,   iliac,    common,   196 

external,   106,   198 

internal,    194,   196 

superficial,   199 
ilio-lumbar,   198 
infraorbital,   185 
innominate,    179 
intercostal,    189 
lingual,   180 
lumbar,   195 

mammary,  internal,  189 
maxillary,  internal,  183 
meningeal,    anterior,    185 

middle,   184 

posterior,   188 

small,   184 
mesenteric,   superior,  194 

inferior,   195 

obturator,    197 

occipital,    181 

ophthalmic,    185 

palmar  arches,   192 

peroneal,   202 
pharyngeal,    ascending,   183 
phrenic,    194 
plantar,    external,   202 

internal,    202 
popliteal,   200 
profunda  femoris,   199 

inferior,    191 

superior,    191 
pudic,    deep   external,   199 

superficial    external,    199 

internal,    197 

pulmonary,   208 
radial,    191 
renal,    195,    268 
sacral,    lateral,    198 

middle,   196 
sciatic,    197 
spermatic,  195 
splenic,   194 
subclavian,   187 
subscapular,   190 
suprarenal,    195 
suprascapular,    189 
temporal,   183 
thoracic,   acromial,   190 

alar,   190 

long,    189,   190 

superior,   190 
thyroid,   inferior,   187 

superior,    180 
thyroidea  ima,   252 
tibial,   anterior,    200 

posterior,   201 
transveralis  colli,   189 
tympanic,    184 
ulnar,    192 
uterine,    198 
vaginal,   198 
vertebral,   188 
vesical,    196 
Arthrodial   joints,    105 
Articulations,    104 

acromioclavicular,   115 
atloaxoid,   107 
carpal,   119 
carpometacarpal,   119 
costosternal,    108 
costotransverse,  108 
costovertebral,    108 
glenohumeral,    116 
occipitoatloid,   107 


Articulations,    occipitoaxoid,    107 

phalangeal,   of  foot,   127 
of  hand,   120 

radioulnar,   117 

sacrococcygeal,    111 

sacroiliac,    110 

sacroischiatic,   110 

sacrovertebral,   110 

sternoclavicular,    114 

tarsal,   125 

tarsometatarsal,    126 

temporomaxillary,    105 

tibiofibular,   123 

vertebral,   106 
Arytenoid    cartilages,    254 
Atlas,    58 
Auricle,    376 
Axilla,    395 
Axis,    44,    58 

cerebrospinal,   296 

celiac,    194 

optic,    358 

thyroid,   188 

visual,   358 
Aaxis    cylinder,    295 
Azygos  veins,  215 

uvulaa,   136 

Bartholin,    duct  of,   230 

glands  of,   292 
Bauhin,   valve  of.   243 
Bell,    external   nerve   of,   336 

internal   nerve  of,   336 
Bladder,   270 
Bodies,    Malpighian,   268 

Pacchionian,  297 

geniculate,    311 

restiform,    299 
Body,   ciliary,   363 

olivary,   299 

pituitary,    306 

restiform,    299 
Bone,    astragalus,   93 

calcaneum,   93 

clavicle,   63 

coccyx,   63 

cuboid,   93 

cuneiform,   78,   94 

ethmoid,   24 

femur,   86 

fibula,  92 

frontal,   8 

humerus,   70 

ilium,    82 

incus,    380 

hyoid,    38 

innominate,    81 

ischium,    84 

lachrymal,    26 

malar,   27 

malleus,   380 

maxillary,   inferior,   35 
superior,   29 

nasal,  27 

occipital,    12 

os  calcis,   93 

os  magnum,  78 

palate,  32 

parietal,   10 

patella,   89 

peroneal,    92 

phalanges   of   foot,   96 
of  hand,   79 

pisiform,   78 


INDEX. 


425 


Bone,   pubic,   S5 
radius.    ~i 
sacrum.   61_ 

scaphoid,   77,   94 

scapula,   65 

semilunar,   78 

sessamoid,   98 

sphenoid,    20 

stapes.    3S0 

sternum,   52 

structure,    microscopic,   5 

temporal,   15 

tibia,    90 

trapezium,    78 

trapezoid.    78 

turbinated,    inferior,    34 
middle,   25 
superior,   25 

ulna,    72 

unciform.    78 

vomer.    35 
Bones  of  the  body,  3 

of  the  carpus,    76 

of  the  cranium.    8 

of  the  face,   26 

of  the  foot,   93 

of  the  hand,   76 

of  hard   palate,   409 

of  the  lower  extremity,  81 

of  the  metacarpus,    76 

of  the  metatarsus,   96 

of  oral  cavity,   409 

of  the  tarsus,    93 

of  the  trunk.    52 

of  the  upper   extremity,    63 

Wormian,    40 
Bonnet,   capsule  of.   360 
Bowman,    capsule   of,    268 
Brain,   commissures  of,   308 

development,    298 

divisions   of,    298 

ventricles,    308 

weights,   average,    29S 
Bronchi,    259 

Brown   stria   of   Retzius,   417 
Brunner's   gland,    242 
Buccinator,   412 

in    artificial    dentures,    412 
Bulb   of   corpus   cavernoflum,    280 

of   corpus  spongiosum,   280 
Bulbi    vfstibuli,    291 
Bulbs,    olfactory,   323 
Burns,   process  of,   402 
Bursas  of  hip,  121 

of  knee,  122 

Cecum,  243 

f'alamus  Bcriptorius,   313 
Calices  of   kidney.   268 
Canal,   alimentary,  223 

auditory  external,  376 
Internal,   18,  387 

carotid,   18 

central,   of  the  cord,  332 

crural.    (00 
I.    30 
loral,    i<m 

for    tensor    tympani,    379 

Hunter's,    199 

hyaloid,   309 

Infraorbital,  30 

Inguinal, 

DUtrii 

of  Huguier,  :;78 


Canal  of  Nuck,  237 

of  Petit,    369 

of  Schlemm,    364 

of  Stilling,    269 

of  the  modiolus,  384 

palatine,    31 

pterygopalatine,    24 

sacral,    61 

spiral,    of   the   cochlea,    384 

Vidian,    24 
Canaliculi,    374 
Canalis  reuniens,   385 
Canals,    membranous,    385 

semicircular,    383 
Canthus,    373 
Capillaries,   175 
Capsule,    external,   310 

internal,    310 

of  Bonnet,    360 

of  Glisson,    246 

of  Tenon,    360 

of  the   lens,    369 
Capsules,   suprarenal,   252 
Caput  coli    (cecum),   243 

gallinaginis,    281 
Carpus,   76 
Cartilages  of  the  larynx,   254 

of  Santorini,    255 

of  Wrisberg,    255 

tarsal,   373 
Cartilagotriticea,    255 
Caruncula   lachrymalis,   373 

myrtiformes,    289 
Cauda    equina,    332 
Cavity,    cotyloid,    81 

glenoid,   of  scapula,   68 

orbital,    42 

peritoneal,    235 

preoral,    412 

sigmoid,   greater,   72 
lesser,   74 
of   radius,   74 
Cells,    auditory,    387 

ethmoid,   25 

hepatic,    246 

of   Purkinje,   318 

mastoid,   17,   378 
Cement,    226 
Cerebellum,   301,    318 
Cerebrospinal   system,   295 
Cerebrum,   302,    320 

convolutions   of,   305 

fissures   of,   303 

lobes   of,   304 
Cervix  of  penis,   279 

of    uterus,    293 
Chorda;   tendinse,    173 
Choroid    plexus,    310 
Cilia,    373 

Circle    of    Willis,    186 
Circulus   arteriosus   iridis,   364 

venosus,  292 
Cisterna  basolis,   297 

magna,   297 

pontis,    297 
Claustrum,    310 
Clavicle,    63 
Cleft    palate,    409 
Clinoid    processes,    21 
Clitoris,    290 

Clivus  Blumenbacb.il,  21 
Cloquct.   canal   of,   369 
Coccyx,    (;:; 
Cochlea,   membranous,   386 


426 


INDEX. 


Cochlea,    osseous,    383 
Coeliac   axis,    194 
Collar-bone,   63 
Colon,    243 

flexures   of,   243 
Columnse   carneas,    173 

papillares,    173 
Columns  of  spinal  cord,  332 
Commissures,    cerebral,    308 

anterior,   308 

middle,    308 

posterior,   308 
Concha,    376 
Condyles   of  femur,   88 

of  humerus,   71 
Coni   vasculosi,   274 
Conjunctiva,   373 
Conus  arteriosus,   172 

medullaris,    332 
Convolutions  of  cerebrum,  305 
Coracoid  process,   68 
Corium,   389 
Cornea,    361 

Cornicula   laryngis,    255 
Cornua   of  thyroid   cartilage,   254 

of   ventricles,    308 
Corona  glandis,   279 
Coronoid   process,   37 
Corpora  albicantia,    306 

cavernosa,   280 

quadrigemina,   314 

mammillaria,    306 

striata,    310 
Corpus    Arantii,    172 

callosum,   305 

dentatum   of   cerebellum,   316 

fimbriatum,   311 

Highborianum,   274 

luteum,    286 

spongiosum,    280 

striatum,   310 
Corpuscles,    Malpighian,    251,   268 

of  the  blood,   175 

tactile,    296 
Corti,   organ   of,   387 
Cortical   substance   of  kidney,   267 
Cotyloid   cavity,   81 
Coverings   of  the  testicle,    273 
Cowper's    glands,    282 
Crest,    lachrymal,   26 

nasal,    31 

of  the  ilium,    82 

of  the  pubes,   85 

of  the  tibia,    90 

turbinated,    31 
Cribriform   tube,    410 
Cricoid   cartilage,  254 
Crista  galli,    24 

terminalis,    170 
Crown,   415 
Crura,   anterior,   311 

cerebri,   306 

of  clitoris,   290 

of -penis,   280 

posterior,    311 
Crusta  petrosa,   226     * 

pontis,    316 
Crypts    of    Lieberkiihn,    242 
Cuneiform    cartilages,   255 
Cuneus,    305 
Cupola  of  cochlea,   386 
Cuticle,   389 


Dartos,    273 

Declivity,    21 

Deciduous    teeth,    414,    415,    418 

Dental    anatomy,    409 

papilla,    415 

ledge,    415 
Dentine,   226,   415  - 
Derma,    389 

Descemet,    membrane,    362 
Diaphragm,    146 
Diaphragma,   sella,   296 
Diaphysis,   3 
Diarthrosis,    105 
Digestion,    organs    of,    223 
Discus   proligerus,   286 
Disk,    optic,    367 
Dorsum  of  scapula,   49,   65 

sella?,    21 
Douglas   cul-de-sac,   237,   284 
Duct,    cystic,   250 

hepatic,    250 

lymphatic,   219 

nasal,   375 
Duct   of   Bartholin,   230 

of  Miiller,   276,   288 

of  Rivini,    230 

of  Steno,    229 

of  Wharton,   229 

of  Wirsung,    246 

pancreatic,   246 

thoracic,    219 
Ducts,   biliary,   250 

ejaculatory,    278 
Ductus  cochlcaris,   373 

communis   choledochus,   250 
Duodenum,    240 
Dura  mater  of  cerebrum,   296 

of  spinal   cord,   332 

Ear,    375 

internal,   382 
Earstones,    386 
Embryology   of  oral   cavity,    409 

of  teeth,    415 

of  lower  jaw,    409 
Emineintia    articularis,    15 

collaterals    (pes    accessorius),    312 
Enamel,   226,   416 
Enarthrosis,    105 
Encephalon,   298 
Endocardium,   173 
Endolymph,    356 
Endosteum,    5 
Epidermis,    389 
Epididymis,    273,   274 
Epigastric   region,   234 
Epiglottis,    254 
Epiphysis,    3,   4 

Epethelial    sheath    of   Hertwig,   41S 
Equator  of   eyeball,   358 
Eruption   of   deciduous   teeth,    415 

of   permanent  teeth,    4,16 
Eustachian   tube,   379 
Eye,    356 

appendages   of,    372 
Eyebrows,   372 
Eyelashes,   372 
Eyelids,    373 

Fallopian    tubes,    287 
Fallopius,    aqueduct  of,    18 

hiatus   of,   18 
Falx   cerebelli,   296 

cerebri,   296 


[NDEX. 


i-j; 


Fascia,    abdominal,    166 

cremasteric,    274 

cribiform,    168 

denta,   312 

iliac,    107 

intercolumnar,    274 

lata.    168 

lumbar.    166 

obturator,    404 

of  Colles,    4u4 

of  the  head   and   face, 

of  the  lower    extremity,    168 

of  the  neck.    166 

of  the  trunk,    166 

of  the  upper   extremity,    167 

palmar.    107 

pelvic,    167 

perineal,    404 

plantar,    169 

rectovesical,    4o( 
Fascia-.    165 
Fauces,   228 
Femus,   86 
Fenestra   ovalis,   378 

rotunda.    378 
Ferrein,    pyramids  of,   268 
Fibrocartilage,    104,    106,    124,    2.".4 
Fibula,   92 
Fillet,    decussation    of,    320 

mesial.    320 

lateral,   320 
Fimbriae,   288 

Fimbriated    extremity.    288 
Fissure,    auricular,    19 

calcarine,    304 

callosomarginal,    304 

collateral,   304 

dentate,    304 

Glaserian,    16 

of  Rolando,    304 

of  Sylvius.    304,    306 

palpebral.    375 

paracentral,    304 

parieto-occipital,    304 

pterygomaxillary,    41 

sphenomaxillary,    40 

sphenoidal.    23.    43 

transverse,    30) 
Fissures   of   cerebellum,    301 

of  cerebrum,    303 

of  liver,    247 

of  spinal    cord,    332 
Floor   of   the  mouth,    413 
Fetal   circulation,    176 

Folds,    palpi  bra  I.    375 

Fontanelles,   59 

Foot 

Foramen    for    Arnold's   nerve,    19 

cecum,   9 

condyloid,    13,    18 

ethmoidal,    24,    16 

for  Jacobson'8   nerve,    19 

infraorbital,    24,     16 

int'i  rior    dental,    410 

int.ervi  rti 

lacerum   anterius,   24,    n 

magnum,    13,   ">o 

mastoid.    16 

mi  dium,    16 

III.  lit;, I.    36,     110 

malar.     II 

nutrient,    .", 

obtui 

of  Monro,  312 


Foramen   of  Scarpa,   31 
of  Stenson,   31 
of  Winslow.    235 
olfactory,    46 

orbital.    24 

ovale,    23 

palatine,    31 

posterius,    13 

pterygopalatine,    22 

rotundum,   23 

sacral,    62 

sphenopalatine,    32 

spinal.    57 

spinosum,    23 

stylomastoid,   10 

supraorbital,    8,    46 

suprascapular,    67 

thyroid,    81 

Vesalii,    23 
Foramina  at  the  base  of  the  skull    46 

cf  hard    palate,    409 

of  mandible,    410 

Thebisii,    171 
Fort  arm,    72,    14'.! 
Fcrmatio   reticularis,    316 
Fornix,    31] 
Fossa,   canine,   20 

caronoid,   71 

digastric,   17 

digital,    88 

glenoid,    16,    68 

hyaloid,   369 

incisive,    20 

infraspinous,    66 

ischorectal,    402 

jugular,    18 

lachrymal,    0 

navicularis   of   penis,   281 

of   vulvo,    289 

olecranon,    71 

ovalis,   171 

pituitary,    21 

pterygoid,    24 

scaphoid,    24 

sphenomaxillary,    44 

sublingual,    36 

submaxillary,    36 

subscapular,    66 

supraspinous,    66 

temporal,    40 

zygomatic,    40 
Fossae,   nasal,    45 

of    the    skull,    40 
Fourchette,    290 
Fovea    centralis.    367 

hemispheric;!.    383 

semielliptica.    383 
Fr<  nuluni,    31 1 
Freiium    lobii,     II  1 

in     relation     to     artificial     dentures, 
412 

preputii,   280 

Call-bladder,     250 
Call-duct,    250 
Ganglia,    295 

basic,    311 

cervical,   3.",2 

crania  I     I  iO 

lumbar.    :::>'■'. 

of  fifth    nerve 

of  the   sympathetic,   350 

sacra  I 

thoracic. 


428 


INDEX. 


Ganglion,   Arnold's,   352 

Gasserian,    350 

irnpar,   350 

Meckel's,    350 

of  Ribes,   350 

ophthalmic,    350 

otic,  352 

sphenopalatine,    350 

spirale,    385 

submaxillary,    352 
Gasser,   ganglion  of,  350 
Geniculate   bodies,   311 
Ginglymus,    105 
Gingival   trough,   411 
Gladiolus,    52 
Gland,    lachrymal,   374 

mammary,    292 

parotid,   229 

pineal,    315 

prostate,    282 

sublingual,   230 

submaxillary,    229 

thymoid,   252 

thymus,   252 
Glandula   coccygea,    253 
Glandula   intercarotica,   253 
Glands,    Brunner's,   242 

Cowper's,    282 

ductless,   250 

gastric,    239 

intestinal,   242 

lachrymal,    373 

lymphatic,   219 

Meibomian,   373 

of  Bartholine,    292 

of  Tyson,   279,   292 

peptic,   240 

salivary,    229 

sebaceous,    390 

solitary,    242 

sweat,   390 
Glans   clitoridis,   290 

penis,   278 
Glenoid,    16,   68 
Glisson's   capsule,   246 
Glottis,    255 
Gomphosis,   105,    414 
Graafian   vesicle,   286 
Groove,    bicipital,   70 

carotid,    21 

cavernous,   21 

infraorbital,    31 

musculospiral,   70 

mylohyoid,    36 

nasopalatine,    35 

optic,    21 
Gubernaculum  testis,   274 
Gums,   224,    411 
Gyri  of  brain,   305 

Hairs,    390 
Hamstrings,    160 
Hamular   process,   26 
Hand,    76 
Hare-lip,    409 
Hard  palate,   409 

sutures   of,    409 

foramina   of,    409 

bones   of,    409 
Haversian   canals,   6 

system,    6 
Head  of  the  femur,   86 

of  the  humerus,    70 

of  the  ulna,    72 


Heart,   170 
Helicotrema,   385 
Helix,   376 

Henle,   tubes  of,  268 
Hernia,   anatomy   of,   396 

femoral,   400 

inguinal,    396 
Hiatus   Fallopii,    18 
Hirlus  of  kidney,   266 
Hippocampus   major,   312;   minor,   312 
His,    bundle  of,   171 
Histogenesis    of   dental    tissues,    416 

of  enamel,    416 

of  dentin,    416 

of  cement,    416 
Hasner,    valve   of,    375 
Houston,   valves  of,   245 
Huguier.   canal  of,   16 
Humerus,    70 
Humor,   aqueous,   368 

vitreous,   368 
Humors   of  the   eyeball,   368 
Hunter's  canal,   199 
Hydatids  of  Morgagni,  276,  288 
Hymen,   288 
Hypochondrium,   234 
Hypogastrium,    234 

Ileum,   241 

Ilium,   82 

Incisura  intertragica,   376 

Incisal   pad,    411 

Infundibulum    of   brain,    306 

Inguinal   regions,    234 

Intestine,    large,   242 

small,   240 
Internal    capsule,    310 
Iris,    363 
Ischium,   84 

Iter  chordae   anterius,   378 
posterius,    378 

e    tertio    ad    quartum    ventriculum 
313 
Ivory,   226 

Jacob's   membrane,    368 
Jacobson's   nerve,   3,16,   336,    365 
Jejunum,    241 
Joint,   ankle-,   124 

elbow-,   116 

hip-,    120 

rotators    of   the,   159 

knee-,    121 

shoulder-,   114 

wrist-,  118 
Joints,   motions  in,    105 

structures   of,   104 

Kidneys,   266 

Labia  majora,   290 

minora,   290 
Labium   tympanicum,    386 

vestibulare,   386 
Labyrinth,    membranous,   385 

osseous,   383 
Lacteals,    219 
Lacuna   magna,    282 
Lacunae,   6 

Lacus   lachrymalis,    373 
Lamellae,   6 
Lamina  cinerea,   306 

cribrosa    (of  sclerotic),   361 
(of  temporal   bone),   18 


IXDEX. 


429 


Lamina  fusca,  361 
reticularis.    387 
spiralis,   3S4 
Lamina   of  cornea,   361 
Lanoisi,    nerves   of,    308 
Larynx,    254 
Layer,    dermoid,    389 
ganglionic,    367 
molecular.   367 
Leg,    90 

Lens,    crystalline,    36S 
Lieberkiihn,   crypts  or   follicles  of. 
Ligament,    annular,   of  foot.    16S 
of   hand,    167 
rhondroxiphoid.    109 
conoid,    115 
coronary,    121 
cotyloid.    121 

crucial,    of   knee-joint,    122 
deltoid,    124 
falciform,    401 
Giiubernat's.    143,    398     400 
glenoid,    116 
iliofemoral   or   Y,    121 
of  Burns.   402 
of  Colles,   398 
of  Hey,    381 
of  Zina,    353,'  369 
orbicular,   118 

Poupart's.    143,    146.    398,    400 
periodontal,    418 
rhomboid,    114 
round,   of  the   liver,   249 

of   the    uterus,    285 
sacrosciatic,    110 
stellate,    108 
stylomaxillarv,    106 
suspensory,    of    lens,    360 
of  liver,   249 
of  penis,   280 
of  spleen,    250 

transverse,    of   hip-joint     121 
trapezoid.    115 

triangular,    of  perineum     104 
Ligaments  of  the  bladder,   271 
broad,    of   uterus,    285 
cheek,    107 

of  the  knee-joint.    121 
of  the  larynx,   255 
of  the  liver,    248 
of  the  ossicles,   381 
of  the  ovaries,   285 
of  the  sternum,    109 
of  the  uterus,    284 
peritoneal,    236-237 
tarsal,    373 
Ligamentum   latum   pulmonis    264 
mucosum,    128 
nuchas,    106 
patella?,   121 
pectlnatum    iridis,   363 
Buspensorium,   108 
teres,    121 
Winslowii,    121 
Limbua   lamina  spiralis    385 
Line,    intertrochanteric,   88 
Linea-aspera,   86 
lliopectlnea,  81 
quadrat! 
Llngula,   i'i 
Liquor    Uorgagni,    869 
Lithotomy,    structures    affected     107 
Liver  1M7 

ligaments,   249 


Liver,    lobes  of,   248 

structure  of,    246 

vessels    of,    249 
Lobes  of  the  cerebellum,   301 

of  the  cerebrum.    302 

of  the  liver,    248 
Lobule  of  the   ear,   375 
Lobules   of   the    liver,    246 

of   the   lung,    262 
Lobulus    caudatus.    246 

quadratus,   246 

Spigelii,   246 
Lower,    tubercle    of.    171 
Lumbar   regions.    234 
Lung,    broad   ligament  of    264 
Lungs,    261 
Lymphatics.   219 

hepatic,    222,    249 

of  lung,    263 

of  penis,    281 

of  trachea   and   bronchi,   260 

of  uterus,    284 
Lymph    spaces   of  eyeball     360 
Lyra,   311 

Macula  acoustica,   385 
c.ribrosa,   383 
lutea,    367 
Malleolus,    92 
Malpighi,    bodies   of,   251 

pyramids  of,   267 
Malpighian   corpuscles,   251.   268 

tuft,   268 
Mamma?,    292 
Mandible,    410 
Mandibular,   canine,   421 
fifth   cuspid,    422 
first    incisor,    420 
first   molar,   421 
first  premolar,   421 
fourth   cuspid,   421 
second   incisor,    420 
second   molar.   421 
second  premolar,   421 
third    molar,    421 
Manubrium   of  the  malleus,   380 

of   the   sternum.    52 
Marrow   of   bone,    5 
Masses,    lateral,    of    ethmoid,    24 
Mastoid   process,    16 
Maxillary,    canine,   419 
first,    419 
first  molar,   419 
first  premolar,   419 
second,    419 
second    molar,    419 
second    premolar,    419 
third   molar,    420 
Meatus   auditorius   externus     18 
interims,    18,    ::s; 
nasi.     1:, 

urinarius,  281,  291 
Meckel's  ganglion,  350 
•Mediastinum,    264 

testis,    274 
Medullar,    5 

oblongata,  299.  315 
Medullary   sheath,   294 

substance,     266 

Membrana    basillaria    3S6 
'  anuloi  a,   286 
prseformativa,   416 
puplllariB,   364 
Ruyschlana 


430 


INDEX. 


Menibrana  tectoria,   387 

tyrnpani,    380 

secundaria,    362 
Membrane,    hyaloid,    369 

interosseous,    119,   120,    124 

Jacob's,    367 

limiting,   367 

of  Descemet,    364 

Nasrnyth's,    415,   417 

of  Reissner,    387 

Schneiderian,    356 

Shrapnell's,    378 

vitelline,    286 
Membranes  of  brain,  296 

of  the  spinal  cord,  332 

synovial,    104 

tarsal   synovial,   126 

wrist  synovial,   120 
Meridians  of  eyeball,   359 
Mesencephalon,    314 
Mesenteries,   236 
Metacarpus,   80 
Metatarsus,   96 
Midbrain,    318 
Modiolus,    384 
Monro,   foramen  of,   312 
Mons   veneris,   290 
Montgomery,    glands    of,   292 
Morgagni,    hydatids   of,   276,   288 

liquor,    369 
Mouth,   223 

Muller,    duct  of,   276,   288 
Muscle,    ciliary,    364 

cremaster,   274 

dilator   pupillse,   364 

levator    glandulse    thyroidea?, 

of  the  auricle,   376 

sphincter    pupillas,    365 
Muscles   of   the   abdomen,   143 

of  Hilton,   258 

of  Houston,   405 

of  the  arm,    148 

of  the  back,    138 

of  the  ear    (external),    129 

of  the  epiglottis,    258 

of  expression,   412 

of  the  Eustachian   tube,   379 

of  the  eyeball,    369 

of  the  face,    130 

of  the  forearm,   149 

of  the  foot,    163 

of  the  hand,    153 

of  the  head,    129 

of  the  hip,    155 

of  the  larynx,   257 

of  the  leg,   160 

of  mandible,   414 

of  mastication,    413 

of  the  neck,  133 

of  the  palate,    135 

of  the  perineum,    407 

of  the  pharynx,    135 

of  the  shoulder,    147    * 

of  the  stomach,    239 

of  the  thigh,  156 

of  the  thorax,    145 

of  the  tongue,    135 

of  the  tympanum,    382 
Muscular  fiber,   128 

floor   of  mouth,   413 
Musculi   pectinati,   172 

Naboth   ovules   of,   284 
Nasmyth's   membrane,    415,   417 


Nails,   390 

Nares,   45 

Nates   of  cerebrum,   314 

Neck   of  femur,   88 

of  humerus,  70 

muscles   of,   133 

triangles   of,    391 
Nerve,    abducens,    326 

Arnold's,   330 

auditory,   328 

Bell's    external    respiratory,    336 
internal    respiratory,    334 

cells,   295 

chorda  tympani,   328 

circumflex,    336 

cochlear,   328 

crural,   anterior,   340 

facial,    326 

fibers,    295 

genitocrural,    339 

glossopharyngeal,   330 

gluteal,    superior,    340 

hypoglossal,    331 

iliohypogastric,    339 

ilioinguinal,    339 

intercostal,    339 

intercostohumeral,    340 

internal   cutaneous,    337 

interosseous,   337,   338 

Jacobson's,   330,   382 

laryngeal,   259,   330 

maxillary   inferior,    326 
superior,   325 

median,    337 

motor  oculi,   324 

musculocutaneous,   337 

musculospiral,    338 

nonus   or   ninth  pair,    330 

obturator,    340 

of   Wrisburg,    337 

olfactory,    323 

ophthalmic   division   of  fifth,   325 

optic,   323 

par  vagum,    330 

patheticus,    325 

petrosal,    external,    351 
large   deep,    351 
large    superficial,    351 
small,    351 

popliteal,   341 

phrenic,   334 

pneumogastric,    330 

pterygopalatine,   351 

pudic,   341 

radial,    338 

sciatic,    great,    341 
small,    341 

spinal   accessory,   331 

subscapular,   336 

suprascapular,    336 

sympathetic,   350 

tibial,    anterior,    342 
posterior,    341 

thoracic,    336 

trigeminus,   325 

trochlear,    325 

tympanic,   328 

ulnar,    337 

vestibular,    328 

Vidian,   351 
Nerve-fibers,   optic,   323 

tissue,    295 
Nerves,    295 

cranial,   323 


INDEX. 


431 


Nerves,    hepatic,   354 
of  ankle-joint,    125 
of  auditory    canal,    377 
of  auricle.    370 
of  bladder.    273 
of  choroid,    363 
of  elbow-joint.    117 
of  Eustachian    tube,    380 
of  eye,    372 
of  eyelids.    372 

of  eye-muscles,    363.    370,    371 
of  hip-joint.    121 
of  iris.    364 
of  Jacobson.    330 
of  kidney.    270 
of  knee-joint.   123 
of  Lancisi.    308 
of  larynx,    259,    330 
of  lung,   263 

of  membrana    tymnani,   380 
of  nasal    fossie,    356 
of  nose,    356 
of  pulp,   418 
of  ovaries,   287 
of  pancreas,   246 
of  pharynx,   230 
of  shoulder-joint,    115,    117 
of  spleen,  251 
of  stomach,    240 
of  suprarenal    capsules,    253 
of  taste,    389 
of  testicles.    278 
of  thymus   gland.    252 
of  tongue,   389 

of  trachea    and    bronchi,   260 
of  tympanum,   378 
of  uterus.    _'M 
of  wrist-joint,    119 
petrosal.    351 
popliteal.    341 
sciatic.    :;n 
spinal.   332 
splanchnics,   353 
table  of,   343 
thyroid,    252 
Nervous   system,   294 
Newman,    sheath    of,   418 
N«  unlemma,   294 
Neuroglia.    295 
Neuroi 
Nipple.    292 
Nose,   355 

Notch,    cotyloid.    81 
Interclavicular,  41 
intercondyloid,    71 

popliteal.    60 

Kivinus.   378 

tic,    84,    85 
old,    37 
supraorbital,  8 
suprascapular,  67 
Nuck,    canal    of.    237 
Nucleus,   red,   318 
Nymphs, 

<i  cross,   is 
protuberance   (i  sternal)     12 

'  malt,     1  1 

Occulsion,    122 
Odont  U6 

L'31 

Omentum,   235 


Opening   saphenous,    168,   401 
Optic  thalami,   311 
Ora    serrata,    365 
Orbital    cavities,    40 
Organ    of   Corti,   387 

of  hearing.    375 

of  Rosenmiiller,   287 

of  sight. 

of  smell,    355 
Organs   of  generation,   female    283 
male,    273 

of  taste,    3S9 

of  voice   and   respiration,    254 

urinary,   266 
Os   ealcis,   93 

orbiculare.    383 

planum    (orbital   of   ethnoid)     24 

tinea?,    284 

uteri,    284 
Ossa  innominata,   81 

triquetra,    40 
Ossification,    7 

table  of,  99 
Ossicles  of   tympanum,   380 
Osteology,    3 
Otoliths,    386 
Ovaries,    285 
Oviducts,   286 
Ovisacs,   286 
Ovules   of   Xaboth,    284 
Ovum,   286 


Pacchionian    bodies,   297 
Palate,   228 
Palpebrae,   373 

Pampinaform   plexus    277    287 
Pancreas,    245 
lesser.    ■.'45 
Papilla   lachrymal,   374 
Papilla?  of  skin,   389 
Parovarium,    287 
Pars  cillaris  retina?,   367 

intermedia,   of  vulva     290 
Peduncles  of  cerebellum.    302 

of  corpus   callosum,    305    306 
Pelvic  girdle,  81 
Pelvis,   112 

of  the  kidney,   267 
Penis,    278 
Perforated   space,   anterior,   306 

posterior.   306 
Pericardium.    170 
Perilymph,    385 
Perineum,    403 
female,      107 

centn,]   tendon   of,   406 
Periosteum.    5 
P<  ridontal    ligament,    418 
Peritoneum,   235 
Permanenl   teeth,    115,  416    11s 
I'<  ronei   muscles,    163 
Pes  accessorius.   312 
hippocampi,  312 
Petit,   canal   of,   369 
Pey<  r's   patchi  s,   242 
Phalanges  of  ear    370 
of  foot,   96 
Of  hand.    SO 
-.    230 

I'ia   mater  oi   brain,  297 

Of  Spinal    cord,     331 
Of   tfie     testes.    274 

Pinna,   or  auricle,   376 
Pituitary   body,   253,    306 


432 


INDEX. 


Plane,    equatorial,    358 

meridional,   358 
Plantar  arch,   169 
Plate,   cribriform,   24 

perpendicular,   24 

pterygoid,   24 
Pleurae,    264 
Plexus,    brachial,   336 

cardiac,    353 

carotid,   352 

cavernous,   352 

cervical,   334 

choroid,   310 

of  fourth  ventricle,   310 

hypogastric,   354 

lumbar,   339 

pampiniform,   277,   287 

pelvic,   354 

sacral,    340 

solar,   354 

splenic,   354 

tympanic,   380 
Plexuses  of  the  sympathetic,  353 
Plica  semilunaris,   373 
Point,   nodal,  358 
Poles  of  the   eyeball,   358 
Pomum   Adami,   254 
Pons  Varolii,   300,   316 
Portal  system,   193,   215,   249 
Porus   opticus,    361 
Pouches  of  membrana  tympani,   378 
Poupart's  ligament,  143,  398,  400 
Prism  stripes  of  Schreger,   417 
Preoral  cavity,  412 
Prepuce  of  clitoris,   291 

of  penis,   279 
Process,    acromion,   68 

alveolar,   31,   36,   410 

angular,   8 

articular,    104 

auditory,    20 

basilar,    14 

clinoid,   21 

condyloid,    37,    72 

coracoid,    68 

coronoid,   37,   72 

enamel,    416 

ethmoidal,   34 

falciform,    401 

hamular,    of   cochlea,   384 

Ingrassias,    23 

jugular,   13 

lachrymal,   34 

malar,    31 

mastoid,   17 

maxillary,   28,   33,  34 

mental,   35 

nasal,   31 

odontoid,   59 

of  pterygoid   plate  of  sphenoid,   23 

olecranon,   71 

olivary,   21 

orbital,   28,   33 

of  Tomes,  416 

palate,   30 

pterygoid,  23,  33 

sphenoidal,    33 

spinous,   4,   23,   56 

styloid,   19 

transverse,   57 

unciform,   25 

vaginal,   19,   22 

vermiform,   243 

zygomatic,  16,  28 


Processes,    ciliary,    364 

clinoid,    21 

of   Ingrassias,   23 
Processus,    cochleariformis,   20 

a   cerebello   ad   medullam    (inferior 
peduncles),   302 
ad    potem     (middle    peduncles), 

302 
ad   testes,    302,   315 

gracilis,   380 
Prominentia    canalis   facialis,   379 
Promontory   of   sacrum,   61 

of  tympanum,   378 
Prostate  gland,   282 
Prostatic  sinus,   281 

urethra,   281 
Pterygoid   processes,   23,  33 
Pubes,   85 

Punctum,    lachrymale,    373  « 

Pulp,   415,    418 

arteries,   nerves,   lymphatics  of,  418 
Pupil,   363 
Pylorus,    238 
Ppramid,    anterior,   299 

posterior,    299 

of   tympanum,   378 
Pyramids   of   Perrein,   268 

of  Malpighi,    267 

of  Wistar,    22 

Radius,   74 

Rami    of   inferior  maxillary,    36 

Ramus   of  ischium,    85 

of  the  pubes,  85 
Receptaculum   chyli,    220 
Rectum,    244 

Regions   of   abdomen,   234 
Reil,    island  of,   304 
Reissner,   membrane  of,   387 
Renal  vessels,  268 
Retina,   365 

Ribes,    ganglion  of,   350 
Ribs,   52 
Ridge,   mylohyoid,   36 

pterygoid,   23 

superciliary,    8 
Rima  glottidis,   257 

oris,    412 
Ring,    abdominal,   398 

crural,    400 

femoral,   400 
Rivinus,   duct   of,   230 
Rugae,   411 
Rods   and  cones   (Jacob's),   367 

of  Corti,   381 
Rolando,    Assure   of,    304 
Rosenmiiller,   organ   of,   287 
Rostrum  of  the  sphenoid,   22 

Sac,    lachrymal,   375 

Saccule,   385 

Sacculus,    laryngis,    257 

Sacrum,    61 

Sacs  of  the  peritoneum,   235 

Santorini,      cartilages      of      (corniculo 

laryngis),    255 
Scala  media,    386 

tympani,    385 

vestibuli,    385 
Scapula,   65 

Scarpa,   foramen   of,   31 
Schindelysis,   105 
Schlemm,   canal  of,   364 
Schwann,    substance   of,   294 


INDEX. 


433 


Sclerotic,   361 
Scrotum.    273 
Scute,    379 
Sella  turcica,  21 
Septum,   crurale,   401 

lucidum,  310 

nasi,   45 

pectiniforme,    280 
Sheath,   crural,  401 
Sehreger.   prism   stripes  of,   417 
Sharpey's    fibers.    417 
Sheath   of  Newman,   418 
Shin,   90 
Shoulder-joint,    116 

blade,  65 

girdle,    63 
Sight,    organs  of,   356 

Sigmoid    flexure.    244 
Sinus  aortici  or  sinus  of  Valsalva,  173 

circularis   iridis,    364 

of  kidney,   267 

of     Morgagni     (sacculus    laryngis), 
257 

pocularis,   281 
Sinuses,    frontal,    10 

of  the   dura   mater,   210 

of  Valsalva.    173 

sphenoidal,   22 
Skin,    389 

Smell,   organ  of,  355 
Space,    anterior  perforated,   306 

popliteal,    396 

posterior   perforated,    306 

of   Retzius.    271 

subarachnoid,    297 

subdural,    297 
Spermatic   cord,   276 
Sphincter   vesicae,   271 
Spinal    cord,    332 

nerves,   table  of,   343 
Spine,    ethmoidal,    21 

nasal    anterior,    27 

of  the  ischium,    84 

of  the  pubes,   85 

of  the  scapula,    66 

of  the  sphenoid,    23 

of  the  tibia,    90 

pharyngeal,   14 

posterior,   32 
Spines  of  the  ilium,   84 
Spinous  processts,   4,  23,  56 
Spleen,   250 

Splenic   flexure  of  colon,   244 
Splenium, 
Spot,   blind,   347 

germinal,    286 

light 

yellow,   380,   365 
Squamous.    15 
Bteno'a  ducts,  229 
Stenson'8   foramina,   31 
St<  mum,   52 
Stilling,   canal  of,  369 
Btomach,  2.% 
Styloid,    19 
Substance,    gray,   294 

of    Schwann,    294 

medullar-. 

white,   294 
lantia    gelatinosa    Rolandi,    316 

nipr.-i 
Bulcl, 
Sulcus  spiralis,   886 

tympanicu 


Suprarenal   capsules,    252 
Surface,    articular,    104 

trochlear,    71 
Sustentaculum    tali,   93 
Sutura,   39 
Suture,   basilar,   39 

coronal,    39 

intermaxillary,    39 

laehrymoethmofrontal,    39 

lambdoidal,    39 

masto-occipital,    39 

mastoparietal,    39 

petro-occipital,   39 

petrosphenoidal,    39 

sagittal,    39 

sphenoparietal,   39 

squamoparietal,    39 

squamosphenoidal,    39 

zygomatic,  39 
Sutures,    facial,    39 

of  the  orbit,    43 

of  the  skull,    39 

of  hard   palate,   409 
Sylvius,    fissure    of,    304,    306 
Sympathetic   system,   335 
Symphysis   pubis,    85 

of    inferior   maxillary,    29 
Synarthrosis,    105 
Synovial    membranes,    104 

Tarsus,    93 

Taste,   nerves  of,   389 
Taste  goblets,   389 
Tenit   hippocampi,    311 

semicircularis,    310 
Teeth,   224,    415,    416 
Tendo-oculi,    360 
Tendons,    128 
Tenon,    capsule   of,    360 
Tentorium    cerebelli,    296 
Testes,    273 

of   the   cerebrum,    315 

descent  of,    276 
Thebesius,   foramina   of,   171 
Thigh,   86 
Thorax,    109 
Thyroid    axis,    188 

cartilage,    254 

gland,   251 
Tongue,    388 
Tonsils,    228 
Trachea,   259 
Tract,    lateral,   388 

optic,    306,    323 
Tracts,    olfactory,    306,    323 
Tractus    spiralis    foraminulentus,    387 
Tragus,    375 

Triangle,    Hesselbach's,   400 
Trigonum    urogenitale,    404 

vesicae,    272 
Trochanters   of  femur,   88 
Trochlea,   71 
Tube,    Eustachian,    379 
Tuber   annulare  (pons   Variolli),  287,303 

cinereum,    306 
Tubercle,    4 

genial,    36 

lachrymal,   31 

of  Lower,    171 

of  tibia,    90 
Tub' rosities,    4 

of  femur,   88 

of  humerus,    70 

of  ischium,   85 
28 


434 


INDEX. 


Tuberosities,    maxillary,    31 

Tubes  of  Henle  (convoluted  tubes),  268 

spiral,    of    Sehachowa,    268 
Tubuli   lactiferi,   292 

seminiferi,   274 

uriniferi,   268 
Tuft,    Malpighian,    268 
Tunica   adventitia,    174 

albuginea,   274 

intima,    174 

media,   174 

Ruyschiana,    362 

vaginalis,   274 

vasculosa,   274 
Tunics    of   eyeball,    360 
Tutamina  oculi,    356 
Tympanum,    378 
Tyson,   glands   of,   279,   292 

Ulna,    72 

Umbilical    region,   234 
Umbilicus,    234 
Umbo,   380 
Uraehus,    271 
Ureters,    270 
Urethra,   281,   291 

bulb   of,  281 
Uterus,    283 

masculinus,   281 
Utricle,   281,    385 
Uvea,   363 
Uvula,   228 

vesicae,   272 

Vagina,   288 

Valley  of  cerebellum,  301 
Valsalva,  sinuses  of,  173 
Valve,    Eustachian,    171 

Hasner,   375 

ileocecal,   243 

mitral,    173 

of  Baulin,    243 

of  Vieussens,    313 

pyloric,    239 

semilunar,   173 

tricuspid,   172 
Valves    of    Kirkring     (valvulse    conni- 
ventes),  241 

semilunar,    172,    173 
Valvulae   conniventes,   241 
Vas  aberrans,   276 

deferens,    276 
Vasa  efferentia,  276 

recta,    276 

vasorum,    174 
Vein,   axillary,   214 

basilic,   214 

cephalic,    214 

cerebral,   211 

cerebellar,   211 

femoral,    218 

iliac,   217 

median,   214 

popliteal,   218 

portal,    215 

radial,    214 

splenic,   215 

subclavian,   213 

suprarenal,    215 

ulnar,    214 

vertebral,   216 
Veins,    174 

azygos,   215 

cardiac,    209 


Veins,   choroid,   211 

hepatic,    215 

iliac,    216,    217 

innominate,   213 

interlobular,   249 

jugular,  external,  212 
internal,   210 

of  bone,   5   . 

of  Galen,    312 

of  head   and  neck,   211 

of  lower   extremities,  218 

of  esophagus,    215 

of  suprarenal   capsules,   215 

of  thymus,    252 

of  trachea  and  bronchi,   261 

of  the  eye,    372 

of  the  kidney,    268 

of  the  larynx,   259 

of  the  lung,    263 

of  the  pancreas,   246 

of  the  penis,    281 

of  the  stomach,    240 

of  the  thorax,   214 

pulmonary,    218 

saphenous,   218 

spinal,   216 

thyroid,    213 

uterine,    284 

without   valves,    174 
Velum,   anterior  medullary,   314 

interpositum,    311 
Vena   cava,    superior,   209 

inferior,    215 
Vena?  comites,   174 

proprise   renales,    268 

rectse,   268 

vorticosse,    337 
Venter  of  the  ilium,   84 

of   the   scapula,    65 
Ventricle  of  the  cord,   332 

fifth,    315 

fourth,    313 

of  the  larynx,  257 

third,   312 
Ventricles,    lateral,    308 
Vertebra   prominens,   59 
Vertebras,    56 
Verumontanum,    281 
Vesalii,    foramen,  23 
Vesical,    germinal,   286 

Graafian,   286 
Vesiculse   seminales,    278 
Vestibule,   291 

of  the  ear,  383 
Vidian  canal,  24 

nerve,    351 
Vieussens,    valve   of,    314 
Villi,   241 
Viscera,    covered    by    peritoneum,    237 

partially,    237 

wholly,    238 
Vitellus,   286 
Vocal  cords,  257 
Vomer,   35 

Vortex  of  heart,   173 
Vulva,    290 

Walls   of   the  tympanum,    378 
Wharton's   ducts,   229 
Whorl   of  heart,   173 
Willis,    circle  of,   186 
Wings  of  the  sphenoid,  23 
Winslow,    foramen   of,   235 
ligament  of,   121 


INDEX. 


435 


AVirsung,    duct   of,    246 
"Wistar,    pyramids   of,    22 
Wormian    bones,    -40 
Wrisberg,    cartilages   of,    255 
nerve  of,   337 


Zinn,  zonula  of,  369 
Zona  pellucida,  286 
Zonula  of  Zinn,  369 
Zygoma,   15,   28 


Date  Due 

f 

'iW 

1     ■      '           s 

i 

, 

91 

. 

«fy 


'*u 


SI 


It 


/Vu 


m^<t 


<&T7^ 


-W  ■  ^Ttk-^t^t^ 


